Answer: B. right atrium --> right ventricle --> left atrium --> left ventricle
Explanation: Deoxygenated blood enters the superior vena cava and inferior vena cava and collects it on the right atrium. It is then pumped up through a valve and enters the right ventricle. Then it is transported by the pulmonary artery to the lungs to become oxygen rich blood. From the lungs oxygenated blood enters into the pulmonary vein and back into the heart and goes inside the left atrium. The blood is pumped again through a valve going to the left ventricle and transported to the body through the aorta which distributes oxygen rich blood.
The answer is that <span>all
veins carry blood back to the heart, except for the pulmonary vein. the
vena cava empty into the right side of the heart, so they technically
bring blood to the
</span>main atrium.
Answer:
The correct option is <u><em>A. they evolved from land mammals.</em></u>
Explanation:
The process of evolution explains how closely one organism is to another based on their common ancestors. Scientists believe that those organisms which show many similarities in their structures or functions might have evolved from a common ancestor in the past.
As in the above-mentioned question, scientists have observed that cetaceans lack gills and breath air, this is a property of land mammals. The cetaceans have fin bones which are similar to the limb bones. As limb bones are present in land mammals, hence they cetaceans and land mammals might have common ancestors in the past.
Answer - B
Fish and reptiles both are ectothermic but fish have gills and reptiles have lungs. Ectothermic organisms do not have an internal mechanism of regulating their body temperature and are dependent on their atmosphere for temperature regulation. Fish, reptiles and invertebrates are examples of ectothermic organisms.
The answer is <span>C) mosses, lichen, grasses, and small shrubs.
This is because mosses don't have roots and are very simple plants, therefore they don't have to "root" themselves into a permanently frozen ground that can't support them.
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