Question

Which of the following animals show “Bottle cells” during the gastrulation stage of development?

• A. Snails
• B. Amphibians
• C. Birds
• D. Mammals

Hint:

Remember: Bottle cells are characteristic of amphibian gastrulation; primitive streak is characteristic of birds and mammals.

Answer 1

The Correct Option is B

Step 1: What are bottle cells?
During amphibian gastrulation, a few cells in the dorsal lip of the blastopore elongate inward and constrict at their apices. These cells take on a bottle-like shape, hence called bottle cells. They initiate the process of invagination that forms the archenteron (primitive gut). Step 2: Check other groups
(A) Snails: Gastrulation occurs by epiboly and invagination, but bottle cells are not reported.
(C) Birds: Gastrulation occurs by formation of the primitive streak; no bottle cells.
(D) Mammals: Gastrulation is similar to birds (primitive streak), not by bottle cells.
Hence, only amphibians show bottle cells.