The right answers are a. Veins have one-way valves... AND b. The contraction of skeletal muscles helps push the blood...
The venous system is equipped with an anti-reflux device: valves "check valves":
these are multiple "check valves", called valves, inserted at different levels within all the veins. The valves are open and help the venous return by directing the blood in the right direction (upwards) during muscle contraction. Valves close, preventing blood from flowing back down during muscle relaxation.
The muscles have a facilitating role in the venous return:
The muscular pumps namely the muscles of the sole of the foot, the muscles of the calf and the thigh, relayed by a passive effect of abdomino-thoracic aspiration linked to breathing, allow the venous return. By contracting, the muscles compress and massage the veins that surround them, chasing the blood they contain.
Indeed, in the absence of physical activity, the muscular pumps are stopped, the valves are open. Thus in the standing position, the difference in pressure between the ankles and the heart prevents an effective venous return.
When the body starts moving, the muscle pumps come into action and after a few steps, the pressure difference between the ankles and the heart decreases allowing a good venous return.
In the sitting position, the pressure difference between the ankles and the heart is still too great. Prolonged immobility, even when seated, compromises drainage. Such conditions promote typical postural venous insufficiency.
A small creek runs through a mature forest, keeping the soil around the creek damp all year. A variety of ferns and several flowering plants thrive in this shady, moist area. Along the higher ground above the creek, many species of flowering plants that need less water grow. If a farmer diverted the creek to water his fields, causing the creek to dry up, what would be the most likely long-term consequence for the ferns and angiosperms in the forest?
Answer:
The correct answer will be both ferns and angiosperms number will decrease in area.
Explanation:
The creek is a geographical term used for the minor tributary of a river. When this creek passes through any forest it can act as a source of water to the plants growing in nearby areas which requires plant for their growth and development.
In the given condition when this creek was diverted to the agriculture land caused drying up of creek which influenced plant life present it that area as:
1. Ferns: they will show a decline in their number as they require water not just for their growth but also to complete their life cycle. Their reproduction is incomplete without water as their male gametes need water for fertilization.
2. Angiosperms: the flowering plants will also decrease in the nearby area as they absorb water to maintain their structure, growth and development like water helps in the opening of petals of a flower (reproductive structure).
Thus, both ferns and angiosperms number will decrease in area is the correct answer.
Which organelle is the primary site of atp synthesis in eukaryotic cells?
a. lysosome
b. vacuole
c. mitochondrion
d. peroxisome?
What role do ribosomes play in carrying out genetic information?
Membranes that surround the brain and spinal cord are called ____.
a. hydrocephali
b. ventricles
c. csf
d. meninges
Vitamin A vitamin C calcium and blank are required to appear on nutritional labels
Answer: Vitamins A, vitamin C, calcium, and Iron
Explanation: :)
The microscope that allows the specimen to appear three-dimensional is the
You are surveying biodiversity on a new island chain. you have counted the number of bird species on one island already. the next island is larger and closer to the mainland than the one you have just surveyed. according to the theory of island biogeography, the total number of its bird species should be _____ than on the current island because the rate of immigration to the new island should be _____ and the rate of extinction should be _____.
Answer:
It is d the answer is D
Explanation:
The client has had asymptomatic sinus bradycardia with a rate of 56 beats/min. the nurse notes the rate has dropped to 46 beats/min. what action does the nurse take?
The motherboard mounts to the case via small connectors called ____. fire wires leds nylon bolts standouts
What type of enzyme in the replisome catalyzes addition of nucleotides to the growing dna strands?
What is the name for the living parts of an ecosystem?
a. biome factors
b. biotic factors
c. abiotic factors
d. aerobic factors?
Answer:
B; biotic factors
Energy transformations are always associated with an increase in the
Energy transformations, whether it be in a light bulb, gas stove, or plants during photosynthesis, always increase the entropy or disorder of a system. This is inherent to the second law of thermodynamics which governs energy transfers.
Explanation:Energy transformations are always associated with an increase in the entropy of a system. This concept originates from the laws of thermodynamics. Specifically, the second law of thermodynamics which states that energy transfers or transformations in a system always result in an increase in entropy, or disorder.
This phenomenon is observable in everyday situations. For instance, when a light bulb transforms electrical energy into light energy, some of the energy is lost as heat - an unordered form of energy, thereby increasing the system's entropy. Similarly, gas stoves transform chemical energy from natural gas into heat energy, again increasing entropy.
Another example is photosynthesis in plants. Here, the energy from sunlight is transformed into chemical energy stored within organic molecules. This transformation is also associated with an increase in entropy, as the process generates heat that is released into the environment. In summary, the primary objective of energy transformations is to increase the system's entropy as a result of energy transfers.
Learn more about Energy Transformations here:https://brainly.com/question/8210521
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Maria loves ice cream, but lately she has become aware that she feels nauseated after eating it. From which condition is Maria to suffering? peptic ulcer heartburn lactose intolerance constipation
Due to a rise in global sea level, a shallow sea covered most of eastern Virginia during the Cretaceous. Virginia had drifted north from the equator and conditions no longer supported the formation of limestone. The tropical climate disappeared, replaced by more temperate conditions. In place of limy sediments, sand and silt were deposited as the sea level receded in the region we now know as the Plateau region. Under these conditions, we would expect to find more fossils of ____________ life forms in this location.
A) marine
B) primitive
C) single-celled
D) terrestrial
answer-D
Calculate the frequency of b cells specific for antigen a on day 36 if the antibody concentration on day 36 is about 8 × 103. (for practice doing calculations with proportions, try this exercise. for practice doing calculations with numbers written in scientific notation, try this exercise.)
Among donna's favorite foods are hot dogs and the traditional cured ham featured in her mother's sunday dinners. what type of cancer is associated with high intakes of donna's favorites
Danny has taken a cross section of a seed. Which of the following are the parts that he will see?
Mars had an orbital period of 1.88 years. In two or more complete sentences,explain how to calculate the average distance from mars to the sun, then calculate it
Mars' average distance from the Sun is 1.52 AU.
To calculate the average distance from Mars to the Sun, you can use Kepler's third law, which relates the orbital period of a planet to its average distance from the Sun. According to Kepler's law, the square of a planet's orbital period (P) is proportional to the cube of the semimajor axis (a) of its orbit.
For Mars, with an orbital period of 1.88 Earth years, you square this period to get P2 = 1.882 = 3.53.
This value is equal to the cube of Mars' average distance from the Sun in astronomical units (AU), a3. To find a, you take the cube root of 3.53, which gives you approximately 1.52.
Therefore, Mars' average distance from the Sun is about 1.52 AU.
Some insects have evolved the ability to pollinate only specific types of flowers. The process of two species evolving together because of interdependence is called
The process of two species evolving together because of interdependence is called coevolution.
Coevolution is the process in which two or more species affect each other’s evolution and mutually depend on each other due to their close ecological interaction. Some pollinators (such as insects, birds) and flowering plants have coevolved for mutual benefit. For example the bird pollinated flowers (ornithophilous) and Humming birds have special adaptions and have evolved a mutualistic relationship. The shape of the flowers fits the birds’ bills and they also possess nectar that suits the bird’s diets. Also, the birds breeding seasons and the blooming period of the flowers have been found to occur at the same time.
The nurse is planning to teach parents about prevention of reye's syndrome. what information would the nurse include in this teaching?
The nurse should emphasize to the parents that they should not give salicylate-containing medications specifically aspirin to a child who has viral symptoms such as chicken pox or flu-like symptoms for it can cause Reye’s syndrome. This rare but serious condition causes swelling in the liver and brain. Signs and symptoms includes confusion, seizures and loss of consciousness that require emergency treatment.
Therefore, parents must not practice self-medication and must always consult a physician before giving any medication to their child.
What is an advantage of using lobster casitas?
A. They improve economic conditions.
B. They increase the lobster population.
C. They prevent diving accidents.
D. They reduce predation on small fish.
Final answer:
B. They increase the lobster population by providing shelter and optimal living conditions, leading to healthier marine ecosystems and enhanced biodiversity, ultimately benefiting fisheries and human economic activities.
Explanation:
The advantage of using lobster casitas is that they increase the lobster population. These structures provide shelter and optimal living conditions for lobsters, which in turn, can lead to rebounds in lobster populations and contribute to healthier marine ecosystems. A similar effect is seen with bivalve beds which serve as nursery areas for various fish and decapods, thereby boosting local fisheries and supporting commercial and recreational fishing activities. In essence, the introduction of artificial habitats like lobster casitas and bivalve beds can enhance biodiversity, promote fish populations, and ultimately benefit human economic activities linked to marine resources.
Vasomotion because of changes in ph or co2 levels would be a result of __________?
Which of the two methods for determining the species taxon would involve greater subjectivity? a. reproductive isolation b. morphology c. both are completely objective
Answer: b. morphology
Morphology is a branch of biology which studies structure of organisms. It studies external and internal features in an organism. For example external features like shape, size, color, pattern etc. and internal features like bones and organs can be studied in an organism. Taxon is the group of one or more organism(s) which forms a unit. Taxon gives the hierarchy for the nomenclature of the organisms from kingdom to subspecies. Reproductive isolation explains the fact that members of different species are prevented from producing viable fertile offsprings because of chief morphology and physiological features present in them. Morphology is the basis for taxonomic categorization and classification of organisms. Every taxa differ morphologically from the other taxa. Morphology gives the identity to species hence would involve greater subjectivity in determining the species taxon.
Gregor Mendel was the first scientist to use statistics to analyze scientific data. Before Mendel’s experiments, scientists believed that organisms acquired traits from their environment and passed them on to their offspring. After Mendel’s discoveries were accepted, scientists realized that traits passed to offspring were the result of genes being passed from parents to offspring. This is an example of
a theory changing because a new scientific method was developed.
a law changing because a new scientific method was developed.
a hypothesis changing because a new scientific method was developed.
an observation changing because a new scientific method was developed.
Answer:
A theory changing because a new scientific method was developed.
Explanation:
Scientists before Mendel did experiments that resulted in the theory that organisms acquired traces of their environment and passed them on to their offspring. However, Mendel established a different scientific method that developed experiments that showed that this theory was wrong. Mendel developed a new theory which, based on his experiments, stated that the traits passed on to the offspring were the result of genes being transmitted from parents to their offspring.
With this, we can say that this is an example of a theory that changed because a new scientific method was developed.
Phospholipid fatty acid tails spontaneously cluster together away from the aqueous cellular interior and exterior environment due to their ____ nature.
A client with eclampsia begins to experience a seizure. which intervention should the nurse do immediately?
Darwin called a mechanism for descent with modification ______.
Which part of the scientific method is represented by the data in th table?
Which policy has been a cost-effective way to reduce sulfur dioxide emissions?
A) enacting cap-and-trade legislation
B) implementing scrubber technology on all power plants
C) burning high-sulfur coal
D) banning the emissions of sulfur dioxide entirely
Answer: B) implementing scrubber technology on all power plants
Explanation:
The scrubber technology is cost-effective technique which can be used to reduce the sulfur dioxide emissions. This technique is useful in capturing the harmful particle and gaseous waste generated from the engines in the chambers. The chambers collect the errant particles and gases such as carbon monoxide, carbon dioxide and sulfur dioxide. Thus the harmful particles and gases are not released in the atmosphere.
On the basis of above description, the scrubber technology should be implemented to control the release of sulfur dioxide emission.
In general, atp is generated in catabolic pathways and expended in anabolic pathways.
a. True
b. False
The affirmation is true. ATP is generated in catabolic pathways and expended in anabolic pathways.
In catabolic pathways, large molecules are broken into smaller ones to release energy, commonly in the form of ATP. These processes are commonly known as exergonic processes.
In anabolic pathways, larger molecules are constructed from smaller units, requiring energy (the process is known as an endergonic process). The hydrolysis of ATP is commonly the reaction that gives the required energy for this kind of processes.