Explanation: Embryogenesis is the process of multiplication of cells by mitosis and formation of tissues and organs of a living baby. It starts once the egg has been fertilized.

Explanation: In the nucleus of the sperm cell normal histones are replaced by a special class of packaging proteins known as protamins which makes the nucleus transcriptionally inactive.

Explanation: Ovoviviparous is the condition where fertilization is internal but there is no placenta formation. Example: dog and fishes.

Explanation: In viviparous, fertilization is internal and nourishment is provided through placenta by the uterine wall of the mother.

Explanation: Egg laying animals fall under the category of oviparous. Here fertilization can be internal or external. Fishes are not oviparous but ovoviviparous, they are not egg laying animals.

Explanation: Animals have been categorized according to the amount of yolk in the egg. Alecithal are those organisms which have no yolk in their egg, e.g. mammals.

Explanation: On the basis of yolk distribution, the egg has been divided into three types, i.e., isolecithal, telolecithal, and centrolecithal. Telolecithal are those in which heavy yolk is present at a vegetal pole and less yolk at the animal pole, e.g. amphibians.

Explanation: Noncleidoic eggs laid in Water or develop inside the mother’s body. These eggs do not have any protective covering around them, e.g., amphibians, fishes, and mammals.

Explanation: Cleidoic eggs are those which laid on land and have a leathery coat around them for the prevention of its dessication e.g., birds, and reptiles.

Explanation: When the cleavage takes place in the form of a disc-like flat layer above the yolk in the animal pole, it is called discoidal cleavage. Discoidal cleavage is found in bird’s eggs.