Question

Which of the following characteristics in birds indicates their reptilian ancestry?

• A. Eggs with a calcareous shell
• B. Scales on their hind limbs
• C. Four-chambered heart
• D. Two special chambers crop and gizzard in their digestive tract

Answer 1

The correct option is B Scales on their hind limbs

Reptiles too are egg-laying organisms. But in aves, the eggs have a calcareous shell around them. In aves, the heart is four-chambered, while in reptiles the heart is 3 chambered and is incompletely divided to form a four-chambered heart. They have two special chambers called crop and gizzard in their digestive tract. Gizzard is modified for grinding food and crop for storing food on a temporary basis.

So, option B is the correct answer.