Answer:
circulatory
Explanation:
Heart is only responsible for generating the pumping force needed to supply blood to each and every corner of the body. As heart is part of circulatory system. The answer is Circulatory system.
D. is a recent development resulting from the burning fossil fuels
I believe it is atom, then tree seedlings, then a cat, then a fence panel, then a pecan tree and lastly the house
<span>3) Oceans
The oceans are a massive carbon sink, and part of the positive reinforcement of the greenhouse gas cycle is that, as the oceans become warmer, then tend to release more carbon dioxide dissolved in the water which in turn drives temperatures warmer.</span>
Answer:
The animals present body structure is due to evolution. It is seen in each part including the structure of the heart. The vertebrate heart becomes complex from a simpler form.
Invertebrates, the heart of fishes is two-chambered having one auricle and one ventricle. The deoxygenated blood gets purified in the gills. They are aquatic and no lungs for breathing. The hearts pump a mixture of oxygenated and deoxygenated blood to the body.
The amphibians and reptiles have 3 chambered heart as they lead terrestrial mode of life. The gills modified into the lungs. The left auricle receives pure blood and the right auricle receives deoxygenated blood. The blood purified in the lungs and in the ventricle, both types of blood get a mix. The ventricle pumps the mixed-blood throughout the body.
In the case of birds and mammal, the heart is 4 chambered and the oxygenated and deoxygenated blood are separated. These two are higher vertebrates. No mix of pure and impure blood, the body receives only the oxygenated blood.
This shows to construct the phylogenetic tree of vertebrates - the fishes should be in the bottom, and above it amphibians, reptiles, then, mammals and birds on the top branch of the tree. As the chambers and structure of the hearts modified one after another.
