Question

External fertilization occurs in
A. Lizard
B. Birds
C. Rat
D. Frog

Answer 1

Hint: External fertilization: In external fertilization the fusion of male and female gametes (sperms and ovum) takes place outside the body of the female. Example: Frog and fish.

Complete answer
A. Lizard – Scientific name of wall lizard is Hemidactylus.The class name refers to their creeping or crawling mode of locomotion.They are terrestrial and their body is covered by dry and cornfield skin.
>They are poikilotherms.
>Lizards shed their scales as skin cast
>Serves are separate and fertilization is internal.
B. Birds – Belongs to class Aves. Characteristics are-
Presence of feathers, forelimbs are modified into wings and hind limbs have scales and help in walking, swimming or (ii) Clasping the tree branches.
Bones are hollow with air cavities (i.e. pneumatic bones).
Birds' digestive tracts have additional chambers, the crop and gizzard.
They are warm blooded (Homoiothermous).
Sexes are separate.
Fertilization is internal.
C. Rat- Scientific name is Rattus
They are found in variety of habitats
Rats are typically distinguished from mice by their size.
Best known species are the block rat (Rattus rattus) and the brown rat (Rattus norvegicus)
They are Homoiothermous.
Sexes are separate and fertilization is internal.
D. Frog:
Belongs to class Amphibia
Scientific name is Rana tigrina.
Sexes are separate and fertilized in the external. They are oviparous and development is indirect.
The female frog lays hundreds of eggs in the water where they are fertilized by the sperms released by the male frog. This type of fertilization is known as external fertilization as in external fertilization fusion of gametes takes place outside the body of the female.

Note: In internal fertilization the fusion of gametes takes place inside the body of the female. Example: Human cats, goat, cow, sheep, dogs etc.