AP BIOLOGY

Detailed explanation-1: -The two atria receive blood from the two different circuits (the lungs and the systems). There is some mixing of the blood in the heart’s ventricle, which reduces the efficiency of oxygenation. The advantage to this arrangement is that high pressure in the vessels pushes blood to the lungs and body.

Detailed explanation-2: -In three-chambered heart, oxygenated and deoxygenated blood gets mixed in the ventricles, Hence the body never receives fully oxygenated blood.

Detailed explanation-3: -In amphibians, the heart is of three chambers that is two atria and a single ventricle. Like humans, these animals also have separate blood circuits for transferring oxygenated and deoxygenated blood. Deoxygenated blood collects the oxygen-deficient blood from the body and opens into the right atrium.

Detailed explanation-4: -The septum ensures that blood does not mix between the right and left ventricles. One feature of truncus arteriosus is a large hole in the septum between the two ventricles (called a ventricular septal defect). This lets oxygen-poor blood mix with oxygen-rich blood.

Detailed explanation-5: -Amphibians can endure certain measures of blending of oxygenated and deoxygenated blood since they don’t need a lot of energy. They change their body temperature when the climate changes. Hence, the correct answer is option (C).