Q.Distinguish the heart of an amphibian from that of a reptile.

[!TLDR] The amphibian heart's ventricle is undivided; the reptilian heart usually has a partial (in crocodilians, almost complete) septum. …

[!ANSWER] Amphibian and reptilian hearts both have two atria and are broadly three-chambered, but differ in how completely the ventricle is divided.

In Amphibia (e.g. the frog), the heart has two atria and a single, completely undivided ventricle. Oxygenated blood from the lungs/skin and deoxygenated blood from the body both enter the ventricle, where some mixing occurs, though a spiral valve in the outgoing vessel (truncus arteriosus) partially directs relatively more oxygenated blood toward the head/body and more deoxygenated blood toward the lungs/skin, limiting (but not eliminating) the inefficiency of this mixing. …

• Assuming both hearts have exactly the same degree of ventricular division — the reptilian ventricle is (at least partially) divided, unlike the amphibian ventricle. …