Embryonic Development | MCQs

Explanation

Explanation

Explanation

Explanation

Explanation

Explanation

The biogenetic law, also known as recapitulation theory, was proposed by Ernst Haeckel.

It suggests that the development of an organism (ontogeny) mirrors the evolutionary development of the species (phylogeny).

Explanation

A protostome is an animal where the first opening that forms during embryonic development (the blastopore) becomes the mouth.

While the second opening develops into the anus. 

Explanation

In Ascidian embryos, the grey crescent gives rise to the notochord. 

The gray crescent:

• In ascidian development, the gray crescent is a region of pigmented cytoplasm located at the posterior of the fertilized egg.
• It is important for determining the future location of the notochord and neural tube. 

Notochord formation:

• The cells derived from the gray crescent are specifically destined to form the notochord, a rod-like structure that provides structural support during development. 

Explanation

Amniotic eggs are present in reptiles, birds and mammals while Non-amniotic eggs are laid by amphibians. And eggs laid by cockroaches called ootheca.