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 !
I did not quite understand that but in pretty sure it is b
It has been linked to lung cancer.
hope this helps!
The mitochondria is the powerhouse of the cell!