Question

Which one of the following statements with regard to embryonic development in humans is correct?

• A. Cleavage division bring about considerable increase in the mass of protoplasm.
• B. In the second cleavage division, one of the two blastomeres usually divides a little sooner than the second.
• C. With more cleavage division, the resultant blastomeres become larger and larger.
• D. Cleavage division results in a hollow ball of cells called morula.

Answer 1

Answer: (B)

In the second cleavage division, one of the two blastomeres usually divides a little sooner than the second.

In the second cleavage division, one of the two blastomeres usually divides a little sooner than the second to form two types of cell inner and outer. The outer cell aligns to form trophoblast while the inner mass of cell forms the developing embryo. The cavity formed is known as a blastocoel and the developed embryo is known as blastocyst.

So, the correct answer is option B.