Question

The most important advancement of mammal over reptile is

• A. The erythrocytes have become enucleated
• B. Presence of thick fur of hairs preventing the heat loss of the body
• C. Presence of placenta, vascular connection between mother and foetus
• D. Presence of diaphragm separating thoracic and abdominal cavities

Answer 1

The correct option is C Presence of placenta, vascular connection between mother and foetus

• Reptiles are cold-blooded, relying on external heat sources to raise their body temperature to a point necessary for activity. They are oviparous. Whereas mammals are warm-blooded, generating their heat internally, retaining it by insulation of fur and/or fat. Having a more consistent body temperature means a more continuous activity level, which means more fuel (food) is required to supply the energy necessary for this active lifestyle.
• They possess the mammary gland, placenta during an embryonic developmental stage. They develop the young one inside the body and nourish their child through a vascular connection between mother and foetus.
• Thus, the correct answer is option C.