Which character is not shared by birds and mammals?

Question

Accepted Answer

The correct option is 4: Viviparity.
Viviparity refers to the mode of reproduction where an organism gives birth to live young that have developed inside the parent's body, rather than laying eggs. This is a defining characteristic of most mammals, where the embryo develops internally and is nourished by the mother until birth. Birds, on the other hand, are oviparous, meaning they lay eggs, and the embryonic development occurs externally within these eggs. While both birds and mammals are vertebrates and share many characteristics, their reproductive strategies differ significantly in this aspect.

The incorrect option is 1: Warm blooded nature.
Both birds and mammals are warm-blooded, or endothermic, meaning they can regulate their own body temperature internally, independent of the external environment. This allows them to maintain a constant metabolic rate and be active in a wider range of temperatures.

The incorrect option is 2: Ossified endoskeleton.
Both birds and mammals possess an ossified endoskeleton, which is an internal skeleton made of bone. This provides structural support, protection for internal organs, and a framework for muscle attachment, enabling movement.

The incorrect option is 3: Breathing using lungs.
Both birds and mammals breathe using lungs. While the structure and efficiency of their respiratory systems differ (birds have a highly efficient unidirectional airflow system), both groups rely on lungs for gas exchange to obtain oxygen and expel carbon dioxide.