Question

Which is correct?
A. Platypus lays eggs
B. Camels have biconcave RBCs.
C. Rat has cloaca
D. Bat has feathers

Answer 1

Hint: Platypus, camels, rat and bat all are mammals and mammals are vertebrates. All mammals are viviparous except duck-billed platypus. Mammas have some characteristic features like hairs, mammary glands, warm-blooded animals, etc.

Step by step answer:Platypus is an egg-laying mammal. They belong to the subclass Prototheria or Monotremata, of mammals. They have cleidoic eggs. They are kept under mammals because they nourish their young ones with their own milk.
-Camels have biconcave RBCs. Camels are an animal of the desert habitation. The water is scarce there. Thus, the RBCs of a camel are oval-shaped. These RBCs can swell up to 250 times their original size. This is a water-conserving adaptation.
-The rat has a cloaca. This is because cloaca is not present in rats. Cloaca is a common opening for the digestive, reproductive, and urinary tracts. Cloaca is present in the embryo of the rats; however, they are absent in the adult animals.
-Bat has feathers. Bat is a mammal. And mammals do not have feathers on their skin. It is a feature of the Aves. The wings of a bat are modified skin that grows between their fingers. They are known as the patagium.
Hence, the correct answer is option (A).

Note: Platypus is also known as the duck-billed platypus because its beak is similar to that of a duck. Its scientific name is Ornithorhynchus. They are considered the connecting link between the reptiles and mammals. Also, they are said to show gynandromorphism.