answer:
plasma membrane a microscopic membrane of lipids and proteins which forms the external boundary of the cytoplasm of a cell or in closes a vacuole, and regulates the passage of molecules in and out of the cytoplasm
answer number 2
the plasma membrane or cell membrane, is the phospholipid layer that surrounds the cell and protects it from outside environment.
you can use either answer if you have to type or write an answer
First answer is , as the work of ventricle is to push blood to he whole body , so it has to be strong or it can not pump blood to head to the toe !
as in frog (an amphibian ) it has only three chambers as two artia and one ventricle, so the oxygenated blood from left artia and deoxygenated blood from right , combines and thus partial oxygenated blood is circulated !