Answer:
So it is saying that Plate tectonics influence earth layers and earth layers influence plate tectonics. Plate tectonics affects minerals and the rock cycle as well as mountain building, and explains earthquakes and volcanoes.
When did Cyanobacteria start producing pure oxygen
Answer:
After the hadeon
Explanation:
The Cyanobacteria start producing pure oxygen after the Hadean eon. The correct option is B.
What is Cyanobacteria?Cyanobacteria, also known as Cyanophyta, are a phylum of microscopic organisms and plastids that obtain their energy from photosynthesis.
They are the primary photosynthetic prokaryotes capable of delivering oxygen.
The name cyanobacteria refers to the color of the microorganisms. After the Hadean eon, cyanobacteria began producing pure oxygen.
Toxins produced by cyanobacteria can affect various parts of the body. Different cyanobacteria species can produce toxins that harm the liver, affect the central nervous system (neurotoxins), and produce toxic alkaloids that harm the kidneys and gastrointestinal tract.
High levels of blue-green algae and their toxins can cause diarrhea, nausea, and vomiting, as well as skin, eye, and throat irritation, allergic reactions, and breathing difficulties.
Thus, the correct option is B.
For more details regarding cyanobacteria, visit:
https://brainly.com/question/2516577
#SPJ5
Your question seems incomplete, the missing options are:
A. During the Hadean eon
B. After the Hadean eon
C. During the Phanerozoic eon
D. After the Proterozoic eon
Which statement best explains how power is generated in a tidal power plant?
A. A barrage releases water as the tide comes in and goes out, turning the plant's turbines.
B. As the water flows through a barrage at high and low tides, it turns the plant's turbines.
C. A barrage holds water at high tide, when the water is released, it turns the plant's turbines.
D. A barrage holds water back when the tides change, the force of this turns the plant's turbines.
B
A barrage is a dam-like structure that is built in the tidal zone of an ocean to capture tidal energy.
Explanation:
It has sluice gates that can be controlled to harness the kinetic energy in the flow of water. The sluice gates also have turbines. During high tides, as the water flows into the barrage, it turns the turbines that generate electricity using the dynamo effect. During low tide, as the water recedes back to the oceans, and the barrage gets emptied, the water flow, again, turns the turbines.
Some barrages first capture the ocean water during high tide, until the dam-like structure is full, without generating electricity. When the tide is low, the sluice gates release the water and the turbines generate electricity. This kind is a one –way power generation.
Learn More:
For more on tidal power check out;
https://brainly.com/question/3336216
https://brainly.com/question/1273978
#LearnWithBrainly
The correct statement that best explains how power is generated in a tidal power plant is (C). A barrage holds water at high tide, when the water is released, it turns the plant's turbines.
To understand why option C is the correct explanation, let's consider the process of power generation in a tidal power plant:
1. Tidal power plants are typically located in areas where there is a significant difference between high and low tides. This difference in water levels is essential for generating power.
2. A tidal barrage, which is a dam-like structure, is constructed across a tidal basin or estuary. The barrage includes a sluice gate that can be opened or closed to control the flow of water.
3. At high tide, the barrage gates are closed, trapping a large volume of water behind the barrage. This creates a height difference between the water levels on either side of the barrage.
4. As the tide begins to fall, the water level outside the barrage drops while the water level behind the barrage remains high due to the trapped water.
5. When there is sufficient height difference, the sluice gates are opened, allowing the trapped high-tide water to flow through the turbines installed in the barrage. The kinetic energy of the flowing water is used to turn the turbines.
6. The turbines are connected to generators, which convert the mechanical energy from the rotating turbines into electrical energy.
7. Once the water level behind the barrage has equalized with the outside water level, the gates can be closed again to start the process anew with the next high tide.
Option A is incorrect because it suggests that water is released both as the tide comes in and goes out, which is not how a typical tidal barrage operates. Option B is incorrect because it does not specify that the water is held back to create a height difference, which is crucial for generating power. Option D is incorrect because it vaguely refers to the force of the tides changing, which does not accurately describe the process of water being held back and then released to turn the turbines.
A healthy way to gain weight would be to simply add more calories to your diet. Group of answer choices
Answer:
A healthy way to gain weight would be to simply add more calories to your diet is a TRUE statement.
Explanation:
The number of "calories" that an individual consumes and burns daily plays an important role in determining his/her weight. A person who consumes more calories than he burns daily could become overweight whereas if a person is consuming fewer calories than what he burns could cause him to lose weight.
The best way to gain weight is to "add more calories" to one's diet while also keeping in mind the number of calories being burnt daily. The newly added calories should sum up greater than the total calories burnt regularly.
Hence, the statement about adding calories in the diet to gain weight is true.
Answer:
True
Explanation:
natural philosophers have long pondered the underlying reasons for color in nature. One common historical belief was that colored objects in nature produced small particles that subsequently reaches our eyes. different objects produce different color particles thus contributing to their different appearance. is this belief accurate or not?
This belief is not accurate
Explanation:
The light wave of different frequencies or of a single frequency when reaches an object different occurrences take place. Such occurrences are- of light absorption, where an object absorbs the wavelength of light and the energy gets converted into heat; the light gets reflected by that object and it might be transmitted too.
An object looks colored because it absorbs the frequencies of a particular color and reflects it. It occurs because the material frequency of the object matches the light frequency and it is different in different object.
Final answer:
The belief that colored objects emit small color particles that reach our eyes is inaccurate. Modern physics teaches that color is due to the reflection and absorption of different wavelengths of light, as demonstrated by Sir Isaac Newton's prism experiments.
Explanation:
The historical belief that colored objects in nature produce small particles that subsequently reach our eyes, contributing to their different appearances, is not accurate according to modern understanding of physics and color perception. The nature of color in objects is due to the absorption and reflection of light. When white light (which contains the full spectrum of colors) hits an object, the object absorbs some of the light and reflects others. The color that an object appears to us is due to the wavelengths of light that are reflected and not absorbed. For instance, a red object looks red because it reflects the red part of the spectrum while absorbing other wavelengths.
In the seventeenth century, Sir Isaac Newton's experiments with prisms demonstrated that white light could be divided into visible spectrum colors, laying the groundwork for our understanding of color theory. This understanding was further extended by the concept of wave-particle duality in light, showing that light can exhibit properties of both waves and particles, but the idea of color particles specifically being emitted from objects to our eyes is a misconception.
what is the basic skeletal pattern of all limbs of animals on earth?
Answer:
The common plan for all limbs: one bone, followed by two bones, then little blobs, then fingers or toes. For Owen, seeing a design in the limbs was only the beginning: when he looked at skulls and backbones, indeed when he considered the entire architecture of the body
The basic skeletal pattern of all limbs in animals on Earth follows a common structure known as the "pentadactyl limb." This term refers to a limb with five distinct segments or digits. The pentadactyl limb is a fundamental feature shared by many vertebrates, including mammals, reptiles, birds, and amphibians.
The pentadactyl limb consists of the following segments, starting from the body and extending outward:
Humerus/Femur: This is the uppermost bone, connecting the limb to the body. In the forelimbs (arms or wings), it's called the humerus, while in the hindlimbs (legs), it's called the femur.
Radius and Ulna/Tibia and Fibula: These are the bones of the lower arm (forelimb) or lower leg (hindlimb). In animals with pentadactyl limbs, there are typically two bones in this segment. The radius and ulna are found in the forelimb, while the tibia and fibula are present in the hindlimb.
Carpals/Tarsals: These are the bones of the wrist (forelimb) or ankle (hindlimb). They form a cluster of small bones that provide flexibility to the limb.
Metacarpals/Metatarsals: These are the bones of the palm (forelimb) or the sole (hindlimb). They connect the carpals/tarsals to the digits.
Digits/Phalanges: These are the individual bones of the fingers or toes. In the pentadactyl pattern, there are typically five digits, although some animals have fewer due to evolutionary adaptations.
To learn more about skeletal
brainly.com/question/31182318
#SPJ3
paracrime signsling is different from other types of signaling in that the signaling molecule
Answer:
Paracrine signaling is different from other types of signaling in that the signaling molecule that is secreted from one cell binds to the receptor of the adjacent cell.
Explanation:
Paracrine signaling occur between two adjacent cells.During paracrine signaling the signaling molecule or ligand is released from one cell and the released signaling molecule binds the the surface receptor of the adjacent cell.
For example transmission of nerve impulse between two neurons through synapse.
Cells in a large multicellular organism communicate with each other by chemical signals. These signals are passed from one cell to another. To receive and respond to a chemical signal, a cell must have a --------------for that chemical.
Answer:
Cells in a large multicellular organism communicate with each other by chemical signals. These signals are passed from one cell to another. To receive and respond to a chemical signal, a cell must have a receptor for that chemical.
Explanation:
To generate a physiological response, all cells in the body have special proteins called receptors. These receptors are involved in detecting a chemical signal and generating a response. The receptors are specific for different kind of chemical signals. For example, a dopamine receptor will bind a dopamine molecule whereas an insulin receptor will be able to bind an insulin molecule. Apart from chemical signals, some cells might also respond to mechanical signals.
Cells in a large multicellular organism communicate with each other through chemical signaling. To receive and respond to a chemical signal, a cell must have a receptor for that chemical.
Explanation:In multicellular organisms, cells communicate with each other through chemical signaling.
Chemical signals are passed from one cell to another, allowing cells to coordinate and fine-tune their functions.
To receive and respond to a chemical signal, a cell must have a receptor for that specific chemical.
Learn more about Cell communication here:https://brainly.com/question/32822872
#SPJ3
what happens to the particles when you put a metal spoon into a pot of boiling water.
5. Which of the following will be directly affected in a bacterial cell that has a mutation in its gene for RNA
polymerase?
(1 point)
DNA replication
transcription
translation
gene regulation
Answer:transcribing
Explanation:
i took the test
Answer:
The correct answer is "transcription".
Explanation:
RNA polymerase is an enzyme that synthesize RNA from DNA. The main function of RNA polymerase in bacteria is to perform transcription: the synthesis of messenger RNA from a DNA template (gene) that is later used to translate proteins. A bacterial cell that has a mutation in its gene for RNA polymerase will be directly affected on the way it performs transcription. The mutation could have a lethal effect on the bacteria, because transcription is a essential process for life.
1. What is a predator?
2. Are all predators animals?
Give examples to support your answer.
Your answer should include at least three complete sentences.
Answer:
There are four commonly recognized types of predation: (1) carnivory, (2) herbivory, (3) parasitism, and (4) mutualism. Each type of predation can by categorized based on whether or not it results in the death of the prey.
Explanation:
Some examples of predator and prey are lion and zebra, bear and fish, and fox and rabbit. The words "predator" and "prey" are almost always used to mean only animals that eat animals, but the same concept also applies to plants: Bear and berry, rabbit and lettuce, grasshopper and leaf.The best-known examples of predation involve carnivorous interactions, in which one animal consumes another. Think of wolves hunting moose, owls hunting mice, or shrews hunting worms and insects.
Word analysis. examine the words and/or phrases for each question below and determine the relationship among the majority of words /phrases. chooses the options that does not fit the pattern.
a.wave height
b.wave period
c.wave refraction
d.fetch
In this example, all of the words that are shown are connected in a certain way, except for the A option wave height.
What are wave height and wave period?Fetch is the defined area in which ocean waves are generated by the wind, it is also referred to as the length of a fetch area.
Wave refraction is the change in the direction of a wave as it passes from one material to another. Wave height is how long the wave is from trough to crest and wave period is the successive time from a point where the wave passes.
Wave duration is the amount of time it takes for successive waves to pass a fixed point, such as a buoy, while wave height normally refers to how tall a wave is from trough to crest.
Therefore, wave height from the options does not fit the pattern.
Learn more about the wave, here;
https://brainly.com/question/25628319
#SPJ6
Describe how breathing is controlled
Which receptor was used when you touched something with a light touch?
Mechanoreceptor
Pain receptor
Thermoreceptor
Answer:
The correct option is A. Mechanoreceptor
Explanation:
Mechanoreceptor can be described as a kind of a sensory receptor that generates the response for mechanical pressure. The receptors which bring light touch sensations are a type of mechanoreceptors which are named as Tactile corpuscles. They are receptors which are present in the nerve endings of the skin and are sensitive for light touches. We can say that they are the receptors which have the highest sensitivity present in them.
! 15 points !
Scientists have observed a sudden explosion in the sun followed by rapid changes in the sun's brightness. Which of these events would most likely occur due to this solar condition?
change in wind velocity
change in Earth's climatic pattern
increase in number of solar eclipses
increase in atmospheric pollution on Earth
Please help
Answer: Change in earth's climatic pattern.
Explanation: It is a known fact that human activities has depleted the earth surface over the years which as a result changes the dynamism at which the sun rays reaches the earth. the ozone layer protecting the earth surface from sun radiation has been depleted over time, this in-turn causing changes in climatic pattern. Activities such as release of emissions (carbon oxide, hydrogen sulphide, among others) directly to earth surface has negative effect on how the sun reaches the earth, hence; exposing the earth directly to sun radiation which now causes changes in climatic pattern.
Yo sup??
the answer to this question is option B ie
change in earth's climatic condition because
the sun affects our climate a lot the UV and infrared radiation helps in maintaining the earth's temperature.
Hope this helps
Observing the size of a herd of elephants that are all the same species would be an observation at the ___________ level.
Question 3 options:
community
ecosystem
population
individual
Answer:
population
Explanation:
Answer:
The correct answer is option "population".
Explanation:
In ecology, a population is defined as a group of organisms living in a particular area or region. An observation of a herd of elephants will be a study at the population level, since it is comprised of a limited number of individuals all belonging to the same species. A study of a community would involve observing different species and their interactions, while a study of an ecosystem would involve studying living and non living components over an extensive geographical region.
14-15) What are the two triggers that initiate binary fission?
Answer:
could you be more pacific
Explanation:
Binary fission in prokaryotes is triggered by DNA replication and cell growth until the parent cell reaches a certain size; then, a protein called FtsZ forms a ring to divide the cell into two identical daughter cells.
Explanation:The two triggers that initiate binary fission in prokaryotes are DNA replication and cell growth to a certain size. Initially, the bacterial DNA is replicated, leading to the formation of two genetically identical copies. As the cell elongates, it reaches a certain size that triggers the construction of a division septum at the cell center. Finally, a cytoskeletal protein called FtsZ forms a ring at the site of cell division, facilitating the separation of the two new daughter cells. This division process allows for the rapid growth of bacterial populations, making it a very efficient method of reproduction in unstable environments.
Which of the following is not a response?
a tree turning its leaves towards the sun
a mushroom appearing wet in the rain
a protozoa contracting when touched
your stomach rumbling when you smell food
Answer:
The correct option is B) a mushroom appearing wet in the rain.
Explanation:
A response is generated when a living body detects a change or event as a signal or a stimulus.
In the option A, the Sun acts as a stimulus. The response is the tree turning its leaves.
In the option C, touch is the stimulus. The contraction of the protozoa is the response.
In the option D, the smell of food is the stimulus. Rumbling of the stomach is the response.
In the Option B, no response is carried out by the mushroom. Hence option B does not show an action or response.
Answer:
B. A mushroom appearing wet in the rain.
Explanation:
It is not a response it just looks wet when it is in the rain.
Are all organisms with similar physical characteristics related to one another? If not, why?
Answer:
Yes, all organisms with similar physical characteristics are related to one another.
Explanation:
Species that have common characteristics are closely related. They can even interbreed with one another. The ones with similar physical characteristics tend to be closer than others. Species may share same physical characteristics because they had common ancestors.
Scientists make a comparison of the DNA of the organisms and find that species with same DNA are related to each other. Two similar organisms may also evolve with time to adapt to their surroundings. There would be different reasons for their evolution. In a nutshell, they are closely related contributing to the ecosystem.
Answer: Yes all organisms with similar physical characteristics related to one another
Explanation: Common ancestor
will give brainlist if right!
Leukocytes are found in lots of places, including an organ in your belly that filters
blood and helps fight infections known as the:
A. Heart
B. Spleen
C. Kidneys
D. Brain
Answer:
B. Spleen
Explanation:
The spleen is part of the lymphatic system. The lymphatic system helps to drain toxins and houses lymphocytes.
Find amino acid for the mRNA code AAG
Answer:
phenylalanine
Explanation:
A base set of triplet called codon codes for a particular amino acid of protein molecule. Protein synthesis takes place in ribosomes found in the cytoplasm. Information on the mRNA is translated by ribosomes and is used to assemble amino acids into specific protein molecules.
15. Which of the processes has more than one type of RNA involved?
Answer:
Translation
Explanation:
Translation is the process by which mRNA is decoded and translated to produce a polypeptide sequence, otherwise known as a protein. This method of synthesizing proteins is directed by the mRNA and accomplished with the help of a ribosome, a large complex of ribosomal RNAs (rRNAs) and proteins. In translation, a cell decodes the mRNA’s genetic message and assembles the brand-new polypeptide chain. Transfer RNA, or tRNA, translates the sequence of codons on the mRNA strand. The main function of tRNA is to transfer a free amino acid from the cytoplasm to a ribosome, where it is attached to the growing polypeptide chain. tRNAs continue to add amino acids to the growing end of the polypeptide chain until they reach a stop codon on the mRNA. The ribosome then releases the completed protein into the cell.
The modern model of the atom describes electrons in a little less specific detail than earlier models did. Why is it that being less sure about the placement of electrons in an atom is actually an improvement over earlier models?
The modern model of atom is unable to show the speed of atoms which make it less sure about its improved version.
Explanation:
The atomic model has under-went a drastic change in the past few decades. The first model was developed by Demoncritus in 450 B.C. which was accurate about the existence of atom as matter particles but he was inaccurate about the divisibility of matters.
Many other scientists have developed various models of atom over time, they are- John Dalton(1800), J.J. Thompson(1897), Ernest Rutherford( 1899), Neils Bohr. Neils Borh talked about the nucleus in his model and about the electrons orbiting the nucleus. However, this modern model lacked the observation of the speed of electrons.
Answer:
The modern model of atom is unable to show the speed of atoms which make it less sure about its improved version.
Explanation:
The formula for logistic growth rate is shown above. A population of salmon has a carrying capacity of 2500 in a small fishery.
What will occur when the population reaches 3000 for the salmon?
A)
The population will stabilize at 3000.
The population can never reach 3000 in this case.
The population will grow because the growth rate will be positive.
The population will decline because the growth rate will be negative.
Answer:
d
Explanation:
The population will decline because the growth rate will be negative. Therefore, option (D) is correct.
What is growth rate?Growth rates are used to calculate the yearly percentage change in a variable. A variable's growth rate may be positive or negative, indicating whether it is rising or decreasing with time. Growth rates may be useful in determining the current and future success of an organisation.
The greatest number of a biological species that can be supported by a particular environment, given the availability of food, habitat, water, and other resources, is known as the carrying capacity of that ecosystem.
Learn more about growth rate, here:
https://brainly.com/question/29334875
#SPJ5
how would you describe the process of evaporating fresh water from seawater?
A) Chemical Change
B) Physical Change
C) Chemical Property
D) Physical Property
The process of evaporating fresh water from seawater is Physical change. So, the correct answer is (B).
What is an Evaporation?
Evaporation is the process in which liquid present on the surface changes into gas phase. It is the process of vaporization. It is the process by which liquid water enters the atmosphere as water vapour in the water cycle.
Evaporation can be seen on dry sunny days when wet cloth get dry easily or when the rain puddles disappear on a hot day. All these are the examples of evaporation in which liquid water is not vanishing, it is evaporating into gas called as water vapour.
Evaporation is the one of the main step in global water cycle. It is a physical change. It is a surface phenomenon in which the molecules having higher kinetic energy escape into the air from the uppermost layer of the liquid.
Thus, the process of evaporating fresh water from seawater is Physical change. So, the correct answer is (B).
Learn more about Evaporation, here:
https://brainly.com/question/5019199
#SPJ2
Which of these are an important part of a scientific process?
A. Testable hypotheses
B. Artistic drawings
C.Total agreement
D. Philosophical questions
Answer:
A.Testable hypotheses
it makes the most sense out of the rest
Testable hypotheses are an important part of a scientific process. Therefore, option (A) is correct.
What is Testable hypotheses?Testable hypotheses are a fundamental aspect of the scientific process. They serve as proposed explanations or predictions that can be empirically tested and evaluated. A testable hypothesis is formulated based on prior knowledge, observations, or existing theories and is constructed in a way that allows for experimentation or data collection to either support or refute it.
A well-formulated testable hypothesis is specific, measurable, and falsifiable, meaning it can be proven wrong if the evidence does not support it. By designing experiments or gathering data, scientists can systematically evaluate the hypothesis and draw conclusions based on the results. The process of testing hypotheses allows for the advancement of scientific knowledge, refinement of theories, and the generation of new insights.
Testable hypotheses are crucial in scientific research as they provide a framework for investigation, promote objective inquiry, and enable the accumulation of evidence-based knowledge in various fields of study.
Learn more about Testable Hypotheses, here:
https://brainly.com/question/28355826
#SPJ2
listed in the item box are individual steps that need to be ordered to find out more information about steps some have more details available when you click drag and drop the steps in proper order by placing each in his correspondent open rectangle be sure that the earlier step is placed next to the number one.
ITEM BANK:
Class Family Genus Kingdom
Order Phylum Species
________________________
1.
2.
3.
4.
5.
6.
7.
Answer:
Kingdom
Phylum
Class
Order
Family
Genus
Species
Explanation:
To classify the numerous organisms, we need a system which helps us to classify all the organisms so that it becomes easy for us to study about them. Carolus Linnaeus, a Swedish botanist developed a system of classification called Taxonomical classification. He classified all living organisms in eight ranks,
domain>Kingdom>Phylum>Class>Order>Family>Genus>Species.
( from general to specific)
Mary has type A blood. Her son Bill has type AB blood. Which blood type does Bill's dad have if he is homogenous for blood
type?
B
O AB
0
Answer:
Bill's dad has blood type B
Explanation:
See punnet squares attached
It's given that the dad's blood type is homogenous -> the two letters must be the same. So we can eliminate AB, we have B and O as the options left
If the dad's blood type is O, using punnet square, we can figure out that it then would be impossible for Bill to have blood type AB (AO = blood type A) --> Incorrect
If the dad's blood type is B, using punnet square, we see that the probability that Bill has blood type AB is 100%
Answer:
B, Bill has blood type B) on edge 2020
What 3 factors cause ocean tides?
Answer:
They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides. Spring tides occur during the full moon and the new moon.
The relationship between the masses of the Earth, moon, and sun and their distances to each other play a critical role in affecting the Earth's tides.
Which factor does not cause tides?
The wind is the primary force that causes ocean surface waves, but it does not cause tides. Tides are the daily changes in the level of ocean water at any given place. The main factors that cause tides are the gravitational pull of the Moon and the Sun
What are the three different tidal cycles that we experience on Earth?
As a result, different tidal cycles can be experienced in different regions of the world. They are called semi-diurnal, diurnal, or mixed semidiurnal tidal cycles.
Learn more about ocean tides here: brainly.com/question/13057084
#SPJ2
Which best describes how ocean currents are created?
O A. Heating differences between the poles and the equator because
of the sun lead to convection.
O B. Wind differences between the poles and the equator because of
the sun's light lead to ocean currents.
O
C. Earth's rotation disturbs ocean waters, leading to a system of
currents between the poles and equator.
Answer:A.
Explanation:
Just did it.
Ocean currents are created by the heating differences between the poles and equator due to solar heating, which leads to convection, and are also influenced by Earth's rotation causing the Coriolis effect.
A is correct
Explanation:The creation of ocean currents is best described by the process of heating differences between the poles and equator due to the sun, which leads to convection. This is because the flow of matter is driven by large-scale convection, where warm water rises and cold water sinks due to changes in density related to temperature changes.
Additionally, the Earth's rotation also plays a significant role by causing the Coriolis effect, which affects the patterns of flow in the oceans. Therefore, both the heating difference and Earth's rotational movement combine to create the system of ocean currents that transfer heat around the planet.
Which of the following is forgetting for a reason, such as forgetting where you parked your
car yesterday so that you can remember where you parked it today?
Select one:
a. Decay
b. Retroactive interference
c. Dementia
d. Motivated forgetting
Answer:
The answer is Retroactive interface but Motivated forgetting is also acceptable.
Explanation:
Retroactive interference is when old information interferes with learning new information. For example, you may have trouble remembering your new telephone number because your old number interferes with it.
Forgetting may also happen through motivated forgetting or forgetting for a reason. Sometimes we intentionally forget information, such as where we parked the car yesterday so that we can remember where we parked it today. We may also forget information that we find unpleasant or that produces anxiety. For example, a person may forget a dentist appointment.
Answer:
Motivated forgetting
Explanation:
Well I took the test and if you look in section 02.06 it says it