Question

Type of fertilization ( external or internal) depends on
A. Structure of egg
B. Size of embryo development
C. Type of storm
D. Both a and b

Answer 1

Types of fertilization implies whether the fertilization is external or internal. External fertilization implies fertilization outside the female womb. Under this sort of fertilization, female give eggs. Internal fertilization is when fertilization takes place inside a woman's womb.

Complete answer:
Fishes, amphibia are aquatic animals. These aquatic animals show external modes of fertilization. That is they lay eggs. Whereas animals like reptiles, birds and mammals show internal mode of fertilization. Evidence of external fertilization is egg. External fertilization does not involve a protective shell.
On the other side internal fertilization involves a protective shell. In terrestrial animals, embryos develop inside the larvae of water. When we talk about terrestrial birds for reptiles. Their egg is covered with a very hard and protective shell that is difficult to break so easily. An embryo develops into this protective and hard egg.
In the case of mammals there is not protected with such a hard and protective layer. In mammals fertilization is internal, that is, fertilization takes place inside the female womb. In mammals zygote forms just after the fertilization. And it stays inside the female till the embryo is not formed.
So, from the above discussion we can conclude that the correct answer is option D.

Note:
There are two types of fertilization: external and internal fertilization. Internal fertilization takes place inside the female body. In external fertilization, females lay eggs. The type of fertilization depends upon the structure of the egg and also on the size of embryo development.