Answer:
The correct answer would be Atria push blood into the ventricles and Ventricles push blood out of the heart.
In humans, four chambered heart is present with two atria and two ventricles.
Deoxygenated blood from all over the body is passed into the right atrium through vena cava (superior and inferior).
Simultaneously, oxygenated blood from the lungs is passed into the left atrium of the heart with the help of pulmonary vein.
Both the atria contract at the same time to drain their blood into respective ventricles.
The ventricles undergo relaxation while receiving blood.
The valves present between the atria and ventricles (tricuspid and bicuspid valve) ensures that the blood flows in one way direction only. They shut down as the ventricles contract and produce the sound "lub".
The ventricles contract simultaneously to pump blood out of the heart. The right ventricle pumps deoxygenated blood into pulmonary artery which takes the blood to the lungs for oxygenation.
The left ventricle passes the oxygenated blood through aorta to all the parts of the body.
The pulmonary and aortic valves prevent the back flow of blood and shut at the same time which creates second sound called as "dub".
Answer:
occurs in an ideal, unlimited environment.
Explanation:
<span>Chlorophyll is any of many closely related green pigments found in cyanobacteria and the chloroplasts of algae and plants, and the function of it is that is absorbs energy from light.</span>
<h2>Question:</h2>
how is the same ploidy level maintained in sexually reproducing organisms generation after generation.
<h2>Answer:</h2>
<u>To</u><u> </u><u>f</u><u>ertilization, the fusion of haploid gametes from two individuals, restores the diploid condition. Thus, sexually-reproducing organisms alternate between haploid and diploid </u><u>stages.</u><u> </u><u>To</u><u> process of meiosis produces unique reproductive cells called gametes, which have half the number of chromosomes as the parent cell.</u>
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<u>#CARRYONLEARNING</u><u> </u></h2><h2>
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Answer:
Preadaptations like tegument and body segmentation could have been used by insects and millipedes to survive in terrestrial habitats.
Explanation:
As crustaceans, millipedes and insects have a protective, hard tegument, which surface is frequently smooth. Some groups can also present spines, bristles, or tubercles. The tegument protects the animals against harmful stimuli of different nature, such as mechanic, thermal, chemical, etc. It is also an effective barrier against pathogen microorganisms and excessive dehydration. In groups like crustaceans and insects, as the external layer gets hard, the tegument constitutes an important support organ. It is composed of a simple, cubic epithelium called hypodermis, and secretes exoskeleton, which is composed of chitin and can also be shaped by calcareous impregnations. Chitin is an impermeable, light y hard substance, that allows life on land without dehydration. Segmentation (repetition of identical anatomical units) is another characteristic in these groups that have helped to domain terrestrial habitats. It seems like segmentation is highly advantageous from an evolution point of view because it is much easier to adapt each segment separately to environmental pressures, responding to different necessities, than adapting the whole body to it, developing a new organ for each necessity. Also, it is a strategy to defend themselves from predators by rolling up.
