Question

Gemmules in sponges are helpful in
a. Digestion
b. Asexual reproduction
c. Sexual reproduction
d. Conserving water

Answer 1

Hint: Sponges form internal buds to overcome the season that is unfavorable for them. These internal buds are known as gemmules. An adult sponge can be developed from such a mass of cell (gemmule).

Complete answer:
Gemmules are produced by sponges as a special body. These gemmules are responsible for performing asexual reproduction. These are also referred to as a mass of cells that helps in the formation of new organisms. They help the sponges to survive in harsh environments. Also, the sponges are capable of carrying out both the sexual as well as asexual reproduction. Sponges carry out asexual reproduction via fragmentation or budding. The buds can be formed externally or internally. Internal buds are known as the gemmules. New sponges are developed from these buds.

Hence, the correct answer is option (B).

On the other hand, digestion in sponges is performed by specialized cells known as choanocytes which are also known as collar cells and sponges reproduce sexually by production of sperms and eggs. Moreover, the amount of water entering the pores is controlled via porocytes.

Note: Desiccation (drying out), anoxia (lack of oxygen) and freezing do not have any effect on gemmules as they are resistant to these harsh environmental conditions. Therefore, gemmules can survive in such conditions for a longer period of time. They can resume their growth once this harsh phase is over. Amoebocytes that are enclosed by spicules form the gemmules which are alike endospores of bacteria.