Correct Answer:

D: Crocodile

Explanation of Options:

Option A: King Cobra  
 • Incorrect.
 • King cobras, like all reptiles except for crocodilians, have a three-chambered heart.
 • Their heart consists of two atria and one partially divided ventricle.
 • This structure allows for some mixing of oxygenated and deoxygenated blood.

Option B: Turtle  
 • Incorrect.
 • Turtles, like most reptiles, have a three-chambered heart.
 • Their heart has two atria and one ventricle, which is partially divided.
 • This allows for some separation of oxygenated and deoxygenated blood, but not as efficiently as a four-chambered heart.

Option C: Chameleon  
 • Incorrect.
 • Chameleons, like other reptiles (excluding crocodilians), have a three-chambered heart.
 • The heart structure includes two atria and one ventricle with partial division.
 • This setup results in some mixing of blood, which is typical for most reptiles.

Option D: Crocodile  
 • Correct.
 • Crocodiles have a four-chambered heart, similar to birds and mammals.
 • Their heart consists of two atria and two completely separated ventricles.
 • This structure allows for complete separation of oxygenated and deoxygenated blood, providing efficient circulation.