Question

Cleidoic eggs occur in
a. Insects
b. Fishes
c. Mammals
d. Reptiles and birds

Answer 1

Cleidoic egg is a type of egg, which has the shell which Separates the egg from the outer environment and it protects the egg from the moisture loss and these eggs are mainly laid by the land-dwelling animal.

Complete answer:
- Cleidoic egg is the type of egg that reptiles and birds lay.
- Even mammalian are also evolved from laying cleidoic eggs to giving live birth and these cleidoic eggs are also called as Amniotic eggs because they develop from amniotes.
- These eggs have shells that are protective in nature and they are laid out of the water.
- These shells are porous in air, and they are also either flexible or calcareous(hard). This Calcareous nature of the shell prevents the egg from desiccation.
- The egg contains all the food that the embryo needs to develop for hatching.
- This cleidoic egg is also called a private little pond, it got the name by the way how it gives water and nutrition to the embryo.
- As the cleidoic eggs are laid on the land, so the Internal fertilization is needed.
- Thus, cleidoic eggs have a number of changes in behavior and because of these changes a more flexible and better brain has been developed.
- Some of the examples include the crocodiles and birds, where they look after and protect their young ones and the mammals are more protective and caring towards their young ones.
- Mammals generally provide milk to their young, and so many lesser mammals raise their young in burrows, etc.

Hence, the correct answer is option (D).

Note: There is some distinction between cleidoic and amniotic eggs, which is a cleidoic egg, which means that any closed eggs that lays on the land, while amniotic eggs are those formed from amniotes, which are reptiles, birds, and mammals.