A controlled experiment _____. is repeated many times to ensure that the results are accurate includes at least two groups, one of which does not receive the experimental treatment includes at least two groups, one differing from the other by two or more variables includes one group for which the scientist controls all variables...........biology

Answer: The brain stem is a terminology used to refer collectively to the midbrain, pons, and medulla oblongata.

Explanation:

The midbrain is composed primarily of the optic lobes, which receive and process visual information it is responsible for reflexes involving eyes and ears. Pons is responsible for the reticular activating system and visceral control. The Medulla Oblongata is responsible for the sensory nuclei, reticular activating system, and visceral control.

Answer:

Vasoconstriction

Explanation:

Vasoconstriction is a process in which blood vessels get narrowed or get constricted by the activities of small muscles present in the wall of the blood vessels. When blood vessels constrict, the flow of blood flow is slow down. This process is to conserve body heat. Thus, by vasoconstriction does not help the animal body to lower the increased body temperature. Whereas vasodilation, sweating, and panting lower body temperature if an animal’s body temperature exceeds the set point.

Answer:

mRNA

Explanation:

The messenger RNA also called mRNA is the type of RNA that serves to carry the genetic information from DNA to the cytoplasm. The mRNA is formed by the process of transcription using the DNA template strand.

The mature mRNA enters the cytoplasm and joins with the ribosome. The nucleotide sequence of mRNA is translated into the amino acids sequence of polypeptides. The nucleotide sequence of mRNA is read in the form of triplet genetic codes by tRNA.  

The nervous system is one of the most important elements for our existence and survival, since it allows the management, organization and functioning of the rest of the corporal systems.

The synapse is a communication mechanism that occurs between two or more neurons in order to massively transmit a nerve impulse in order to coordinate a function in the organism.

The Chemical Synapse is the type of major synapse in our body. In these synapses the information is transmitted chemically, through the sending by the presynaptic neuron of different neurotransmitters that the postsynaptic neuron captures through different receptors, whose action generates an alteration in the form of excitatory or inhibitory postsynaptic potential that may end or not with the generation of an action potencial by the postsynaptic neuron. They are versatile synapses, since some neurons can inhibit the action of others depending on what is activated. There is no physical contact between both neurons.

Answer:

the answer is the epithelial plates.

Explanation:

this plate allows height and hardens at the age of around 17-20 years old when the youth is done growing.

Answer:

Interneurons enable the communication between afferent and efferent neurons.  

Explanation:

Internerons are also known as relay neuron. These neurons are classified into local neuron and relay neuron. Interneurons are involved in the process of reflex action and neurogenesis.

Interneurons are known to create neural circuits between the afferent and efferent neuron. This circuit helps in communication and transfer the information between afferent and efferent neurons.

Answer:

Differences between Sympathetic and Parasympathetic

1. Anatomical: The location of preganglionic neurons of the autonomic ganglia and the extension of preganglionic and postganglionic fibers are different in these two systems;

2. Pharmacological: In the Sympathetic system we have the presence of Cholinergic fibers (Ach) and in the Parasympathetic system we have the presence of Noradrenergic fibers (NE);  

3. Physiological: They act antagonistically, they rarely work harmoniously synergistically in coordinating visceral activity (balance)

The sympathetic nervous system readies the body for action, while the parasympathetic nervous system helps the body relax and recover. Sympathetic and parasympathetic divisions of the autonomic nervous system work in opposition to each other, regulating different bodily functions.

The sympathetic nervous system prepares the body for 'fight or flight,' whereas the parasympathetic nervous system allows the body to 'rest and digest.' Sympathetic neurons release norepinephrine onto target organs; parasympathetic neurons release acetylcholine. Activation of the sympathetic nervous system increases heart rate and blood pressure and decreases digestion and blood flow to the skin. Activation of the parasympathetic nervous system decreases heart rate and blood pressure and increases digestion and blood flow to the skin.

Answer:

The answer is A muscilar dystrophy

Explanation:

Progressive muscular dystrophy, which shows the patient by the symptoms that were manifested from three years of age and who started with walking on his toes and the difficulty in raising the legs accompanied by progressive weakness confirm this diagnosis worsening his clinical manifestation at nine years of age, where there is a marked skeletal muscle deformity that makes the use of a wheelchair necessary. we can discard miestemia gravis and multiple scoliosis because they are not pathologies of this age group, polio in turn is a contagious infectious disease that is eradicated in much of the world, mostly in developed countries thanks to the vaccine.

The most likely cause of the described symptoms is Muscular dystrophy.

The disorder that is most likely the cause of the described symptoms is Muscular dystrophy. Muscular dystrophy is a genetic disorder that causes progressive weakness and degeneration of the muscles. The symptoms described, such as walking on toes, waddling gait, frequent falls, difficulty in getting up, and difficulty in lifting knees, are characteristic of muscular dystrophy.

The other disorders can be eliminated:

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Answer:

Veins

Explanation:

Blood returning to the heart from the pulmonary circuit first enters the veins.

Blood returning from the pulmonary circuit enters the heart at the left atrium.

This is a part of the circulatory system process that helps deliver oxygen-rich blood to the rest of the body.

Blood returning to the heart from the pulmonary circuit first enters the left atrium.

The blood travels from the lungs, where oxygen has just been absorbed and carbon dioxide has been expelled, through the pulmonary veins and into the left atrium.

Ultimately, the oxygen-rich blood will be pumped to the rest of the body.

This process is part of the circulatory system, which delivers nutrients and oxygen to cells and removes waste products.

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Answer:

Renal cortex

Explanation:

The renal medulla of a kidney is surrounded by renal cortex. The renal cortex is the granulated layer. It is the renal cortex in which the renal corpuscle (glomerulus and Bowman's capsule) are present. The renal cortex is reddish brown in color. This is due to the fact that most of the renal arteries deliver the blood to the cortex.

Answer:

There will be [tex]50[/tex]% chances of occurrence of a  homozygous recessive progeny

Explanation:

Complete dominance is a situation in which the trait which is considered as dominant overshadow the trait represented by recessive allele.

Hence Q will always over dominate q

Thus, when next time a cross is carried out between homozygous recessive individual (qq) and heterozygous individual (Qq), the following offspring will be produced-

q q

Q Qq Qq

q qq qq

Thus, as we can see out of four offspring , two have homozygous recessive progeny i.e qq

Hence, the chances of occurence of a  homozygous recessive progeny again is equal to

[tex]\frac{2}{4} * 100\\= 50[/tex]%

Answer:

Dehydration reaction includes removal of water molecule from compounds to facilitate formation of bonds between them while hydrolysis reactions break the compounds by breaking the bonds.

Dehydration reactions form the complex macromolecules while hydrolysis reactions break them down into the simpler elements.

Explanation:

During dehydration reactions, removal of a water molecule from two compounds leads to the formation of a covalent bond between them. These reactions are mainly part of anabolic pathways. Two amino acids are joined together by peptide bond and a water molecule is released during the reaction.

Hydrolysis reactions are the opposite of dehydration reactions and are involved in catabolic pathways of macromolecules. The peptide bonds between amino acids are broken down by hydrolysis.  

Dehydration reactions involve the formation of new bonds, while hydrolysis reactions break bonds and release energy. Each macromolecule is broken down by a specific enzyme.

Dehydration and hydrolysis reactions are catalyzed, or "sped up," by specific enzymes; dehydration reactions involve the formation of new bonds, requiring energy, while hydrolysis reactions break bonds and release energy. These reactions are similar for most macromolecules, but each monomer and polymer reaction is specific for its class. For example, in our bodies, food is hydrolyzed, or broken down, into smaller molecules by catalytic enzymes in the digestive system. This allows for easy absorption of nutrients by cells in the intestine. Each macromolecule is broken down by a specific enzyme. For instance, carbohydrates are broken down by amylase, sucrase, lactase, or maltase. Proteins are broken down by the enzymes pepsin and peptidase and by hydrochloric acid. Lipids are broken down by lipases. The breakdown of these macromolecules provides energy for cellular activities.

Answer:

Botulinum is a toxin that can be used to cure wrinkles in human beings by injecting it in very small concentrations and it works in preventing the signals from the nerve cells to muscles and thus paralyzing them by stopping wrinkle formation.

Wrinkles are caused by the contraction of muscles and this neurotransmitter does not allows the muscles to contract. In order to contract nerves release a chemical messenger called as acetycholine. This neurotransmitter is found at the junction where the nerve cell reaches the muscle cell. This causes contraction of muscles.

Injecting botulinum prevents the release of acetylcholine which prevents the contraction of muscle, causing reduction in wrinkles and muscles become stiff.

Answer:

It is easy to confuse a spinal block and spinal epidural because they are both injections into the spinal area. For a spinal block, narcotics or anesthetic is injected once with a needle. For a spinal epidural or combined spinal epidural, a catheter is placed in the epidural space to allow continuous anesthesia.

Explanation:

Answer:

The answer to the question: Class II MHC proteins are found on which of the following cell types, would be: on macrophages and lymphocytes, particularly T-Cells.

Explanation:

MHC, or Major histocompatibility complex, is a very important part of the immune response that the body gives against an invading pathogen, or other foreign substances. There are three types in the human body, Class I, Class II and Class III and each of them will play a role on the cellular membrance of different types of cells and mediate different types of responses. In the human body, this histocompatibility complex is best known as HLA, or human leukocyte antigen, and it will ensure the recognition, or non-recognition of substances, tissues, and other organisms, by the human immune system. Class II, as mentioned before, are most usually found on the immune cells macrophages and lymphocytes, and they are the ones responsible for presenting antigens to these proteinic antibodies so that the immune cells can initiate a proper immune response.

Class II MHC proteins are present on professional antigen-presenting cells such as macrophages, dendritic cells, and B cells.

Class II MHC proteins are found on a specific group of cells within the immune system known as professional antigen-presenting cells. These include macrophages, dendritic cells, and B cells. Unlike MHC I molecules that are found on all nucleated cells, MHC II molecules play a crucial role in the adaptive immune response by presenting abnormal or nonself pathogen antigens to T cells, leading to their activation.

Answer: A. glomerulus.  

Explanation:

Each kidney has about 1 million nephrons, the urine-forming unit, and each nephron is made up of a glomerulus (capillaries walls) and renal tubules. The glomerular is constituted by the capillaries walls, which branch out and form a network, covered by the Bowman's capsule that retains the liquid, and begin to form a sequence of tubes.

The blood reaches the kidneys through the renal artery, which branches into the afferent arterioles that attach to the glomerular capillaries (where blood is filtrated), then form the efferent arteriole, which again becomes capillaries - the peritubular capillaries, which surrounds the renal tubules.

Answer:

All parasympathetic target organs

Cholinergic nicotine receptors, which transmit signals in the nervous system and muscles, are not found in red blood cells, whose function is to carry oxygen and carbon dioxide.

Cholinergic nicotine receptors are found in many areas throughout the body, particularly in the nervous system and muscles where they play a crucial role in transmitting signals. However, you wouldn't find cholinergic nicotine receptors in red blood cells. The function of red blood cells is to transport oxygen from the lungs to the body's tissues and carbon dioxide from the tissues back to the lungs. These cells, unlike neurons or muscle cells, do not have the need for synaptic signal transmission, thus they do not have these specific receptors.

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Answer:

2) JG cells are present in the vasa recta.

Explanation:

The vasa recta is a web of the blood capillary which supply blood to the medulla region of a kidney due to its high permeability of solutes and water. It runs parallel to the loop of Henle. It does not composed of the  juxtaglomerular cells (JG cells). The juxtaglomerular cells (JG cells) present in kidney which synthesise and stores enzyme renin. Thus, option 2) JG cells are present in the vasa recta is not a true statement.  

Answer:

A) [tex]2.150 * 10^{22}[/tex]

B) 1.57 grams

Explanation:

Given -

Amount of gas exhaled in one single breathe [tex]= 0.080[/tex] liters

[tex]22.4[/tex] liter of carbon dioxide contains [tex]6.022 * 10^{23}[/tex] molecules

One liter of carbon dioxide contains [tex]= \frac{6.022*10^{23}}{22.4}\\= 2.688 * 10^{23}[/tex]

A) Number of molecules in [tex]0.08[/tex] liter of carbon dioxide [tex]= 0.08 * 2.688 * 10^{23}\\= 2.150 * 10^{22}[/tex]

B) Mass of [tex]6.022 * 10^{23}[/tex] molecules is equal to [tex]44[/tex] grams

Mass of one molecule [tex]= \frac{44}{6.022*10^{23}} \\= 7.306*10^{-23}\\[/tex]

Mass of molecule is[tex][tex]7.306*10^{-23} * 2.150 * 10^{22}\\= 1.57\\[/tex][/tex]  gram

Taking into account the rule of three:

In first place, the rule of three is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them.

That is, what is intended with it is to find the fourth term of a proportion knowing the other three.  

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied.

To solve a direct rule of three, the following formula must be followed, being a, b and c known data and x the variable to be calculated:

a ⇒ b

c ⇒ x

So: [tex]x=\frac{cxb}{a}[/tex]

To find the number of carbon dioxide molecules, you know that 22.4 liters of CO₂ contain 6.022×10²³ molecules.

If you exhale about 0.0800 liters of CO₂ (carbon dioxide) gas in a single breath, you can aply the following rule of three: if 22.4 liters of CO₂ contain 6.022×10²³ molecules, 0.0800 liters contain how many molecules?

[tex]amount of molecules=\frac{0.0800 litersx6.022x10^{23} molecules}{22.4 liters}[/tex]

amount of molecules= 2.15×10²¹

Finally, the number of carbon dioxide molecules you exhale in each breath is 2.15×10²¹.

To find the mass of the CO₂, you know that 6.022×10²³ molecules have a mass of 44.0 grams.

If you exhale about 2.15×10²¹ molecules of CO₂ (carbon dioxide) gas in a single breath, you can aply the following rule of three: if 6.022×10²³ molecules have a mass of 44.0 grams, 2.15×10²¹ molecules contain how much mass?

[tex]mass=\frac{2.15x10^{21}moleculesx44 grams }{6.022x10^{23} molecules}[/tex]

mass= 0.157 grams

Finally, the mass of the CO₂ you exhale in a single breath is 0.157 grams.

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Answer:

Rupture of the cell, releasing cytoplasmic contents.

Explanation:

Rupture of the cell to release the cell content into the intercellular space occurs in necrosis. This event does not occur in apoptosis. Release of the cell content into the intercellular space in necrosis results in stimulation of inflammatory response. Apoptosis does not include inflammatory reaction and hence, the cells do not rupture to release their content.

This is the washing away of the topsoil (including agricultural chemicals applied in the soil) by surface runoffs into rivers and water bodies after precipitation.

Agricultural runoff can be prevented by adopting good farming management practices such as rotation farming to prevent loosening the topsoil such that it is easily eroded by runoffs. It can also be done by avoiding farming in floodway zones such as in the banks of rivers.

Agricultural runoff is water carrying pollutants like fertilizers from farmlands to water bodies, leading to eutrophication and 'dead zones'. To prevent this, farmers can use buffer strips and contour farming methods.

Agricultural runoff refers to water that collects and carries away various pollutants from agricultural lands into lakes, rivers, and oceans. This runoff can include excess fertilizers, containing nitrogen and phosphorus, which leads to eutrophication. Eutrophication is a process where excess nutrients stimulate excessive plant and algae growth, which, when they die and decompose, increase the biochemical oxygen demand. This process can eventually create 'dead zones' in water bodies where aquatic life cannot survive due to lack of oxygen. To prevent agricultural runoff, farmers can employ several strategies. One example is the use of buffer strips, which are areas of vegetation planted between farmlands and waterways that act as a filter for pollutants. Another method is the implementation of contour farming, where crops are planted across the slope of the land, which helps to reduce erosion and runoff.

Answer: Higher concentration; Lower concentration.

Explanation: The food that we eat undergoes digestion and breaks down into smaller components.

These small components of the food needs to be absorbed first by the process of diffusion.

The water molecules along with the electrolytes are absorbed from an area of its higher concentration in the lumen is transported to area where its concentration is very low.

Hence, the correct answer is diffusion, which is responsible for the transportation of products from one place (higher concentration) to another parts (lower concentration)in the body.

Digestive products like water and electrolytes are absorbed by diffusion, moving from an area of higher concentration in the intestinal lumen to an area of lower concentration in the cells. This happens both in the context of water and electrolytes and is guided by concentration gradients. The small intestine is the primary site for these absorption processes.

Some digestive products, such as water and electrolytes, will be absorbed by diffusion. They diffuse from an area of higher concentration in the intestinal lumen to an area of lower concentration in the cell. This is a process driven by concentration gradients. The small intestine absorbs most of these substances with the aid of its absorptive cells and specialized structures like the microvilli.

For example, each day, about nine liters of fluid, containing water and electrolytes, enter the small intestine from ingested food, beverages, and GI secretions. About 90% of this water is absorbed in the small intestine, moving from an area of higher concentration in the chyme (the digestive substance in the lumen) to an area of lower concentration in the epithelial cells of the intestine. Similarly, electrolytes dissociate into ions in water and most of them are absorbed via active transport mechanisms throughout the small intestine.

Water movement in the body is facilitated by osmosis, a specialized form of diffusion. Water flows from regions of higher concentration to regions of lower concentration along an osmotic gradient across semi-permeable membranes, helping maintain an appropriate balance of solutes inside and outside of cells to ensure their proper function.

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Answer:

The correct option is : A. the most reproductively successful in an environment.

Explanation:

The phrase ''survival of the fittest" originated from the evolution theory given by Darwin. In the Darwin's theory of Evolution, this phrase was used to describe the process of natural selection, which defines the concept of fitness as the reproductive success. Therefore according to this theory, the species which will leave the most copies of itself in the successive generations will survive.

Therefore, the term “survival of the fittest” refers to the most reproductively successful in an environment.

The term “survival of the fittest” refers to individuals who are most reproductively successful in an environment, highlighting the essence of natural selection as the mechanism by which species evolve. Therefore, the correct answer is A. the most reproductively successful in an environment.

The term “survival of the fittest” does not imply that only the physically strongest or largest survive, but rather refers to those more reproductively successful due to traits that confer survival advantages in their environment. Natural selection, another term for “survival of the fittest,” operates when individuals with beneficial traits are more likely to reproduce and pass those traits to future generations. This evolutionary mechanism is central to the theory of evolution, elaborating on how species adapt over time through the differential survival and reproduction of individuals.

It's essential to understand that the 'fittest' in this context is about reproductive success and the ability to pass on advantageous traits that increase an organism's chances of survival, not necessarily brute strength or speed. A classic example is the development of antibiotic resistance in bacteria; those with genetic mutations that resist antibiotics are more likely to survive and reproduce, spreading this trait within the population.

Answer: b. the work rate or oxygen uptake where there is a systematic rise in blood levels of lactic acid

Explanation:

Currently, the anaerobic threshold is one of the most commonly used parameters, both as an indicator of physical performance capacity and training prescription, and there is evidence that performance in continuous and prolonged exercises correlates better with the anaerobic threshold than with maximum aerobic power. The anaerobic threshold can be understood as the point of imbalance between lactate production and removal (blood lactate threshold).

Answer:

The reaction of Glucose + Glucose → Glycogen is called glycogenesis and is an anabolic reaction.

Explanation:  

Metabolic reactions can be anabolic or catabolic. Anabolic reactions are those where small molecules are joined to form a larger molecule; and the use energy. On the other hand, catabolic reactions are those where large molecules are broken in smaller molecules; and they release energy.  

Glucose molecules are smaller than Glycogen. For this reason, the metabolic reaction of Glucose + Glucose → Glycogen is an anabolic reaction called glycogenesis.

glycogenesis  

Two types of metabolic reactions take place in the cell: 'building up' (anabolism) and 'breaking down' (catabolism).

Anabolic reactions use up energy. They are endergonic. In an anabolic reaction small molecules join to make larger ones. For example, the following condensation reactions that occur in cells are anabolic:

The best indicator of one's ability to keep a high-intensity aerobic exercise is Maximal oxygen debt thus option A is correct.

The maximum actuated oxygen deficit is the measurement for the capacity for the anaerobic oxygen that is uptake. This refers to the predicted demand for the oxygen and the oxygen uptake measured during the extensive exercise. It is available for oxidative metabolism and develops at the time of intensive body activity.

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Answer:

176m.u.

Explanation:

Map distance can be calculated by the following formula:

Map distance = [tex]\frac{\text{Recombinant off spring}}{\text{total number of offspring}}\times 1000[/tex]

Recombinant offsprings are redeyes, miniature wings + white eyes, long wings.

Recombinant offspring = 40 + 48

=88.

Total number of offspring = 204 + 208 + 40 + 48

= 500

Map distance = [tex]\frac{88}{500}\times1000[/tex]

Map distance = 176 m.u.

The map distance between two genes is 176 m.u.

Answer:

show the statements

Explanation:

melatonin is a hormone secreted by the pineal gland and its main function is to regulate sleep rhythm (circadian rhythm)

Answer:

High diastolic pressure can leads to kidney damage, vision less and chronic renal failure.

Explanation:

Diastolic pressure may be defined as the blood pressure in the arteries when the heart is completely filled. When the blood pressure is measured the lower value of blood pressure indicates the diastolic blood pressure.

Different problems associated with high diastolic pressure are:

Kidney damage: The high blood pressure can cause the narrow areteies around the kidney and may result in kidney damage.

Vision less: The blood vessel may damage in high diastolic pressure that may hinder the blood flow in the retina and results in vision less.

Chronic renal failure: High diastolic pressure damages the renal artery and causes chronic renal failure in an individual.