Question

In an organism, the zygote undergoes cleavage to produce an 8-16 celled morula. The morula undergoes blastulation to form a structure called blastula. In mammals, the blastula is also referred to as

• A. Blastoderm
• B. Blastocoel
• C. Blastopore
• D. Blastocyst

Answer 1

The correct option is D Blastocyst

The 8-16 celled structure, morula, is a solid sphere of cells without a central cavity. At the 32 celled stage of the morula, fluid enters inside it and collects in between the blastomeres. Morula then undergoes blastulation to form the blastula. In mammals, the blastula is also referred to as the blastocyst.
The blastomeres then reorganise themselves around a large fluid filled cavity called the blastocoel (cavity of blastocyst).
The cells of the blastula form an epithelial layer called the blastoderm.
Blastopore is the opening of the archenteron (cavity of gastrula).