Question

The important features of sponges is
A. Choanocytes in all
B. Sexual reproduction in all
C. Coelenteron in all
D. All herbivorous

Answer 1

Hint: Sponges are multicellular and heterotrophic organisms. They lack cell walls and also produce sperm cells. Unlike other animals, they lack true tissues and organs. Some of the sponges are radially symmetrical, but most are asymmetrical. They have specialized structures called collar cells.

Complete answer:
The sponges have water transport or the canal system.
The water enters through the minute pores in the body wall into a central cavity called spongocoel, from where it goes out through the osculum. The choanocytes or the collar cells line the spongocoel and the canal. The structure of a choanocyte is critical to its function, which is to generate a water current through the sponge and to trap and ingest food particles by phagocytosis. Sponges have the ability to reproduce both sexually and asexually and are omnivores. The phylum Coelenterates includes members with coelenterates, while the sponges belong to the phylum Porifera. Some of the general characters of the sponges are listed below:
i. Habitat: All the sponges are aquatic, mostly marine, rarely freshwater. The sponges like warmer water. They are not usually found in the cold water.
ii. Germ Layers: Sponges are the first multicellular diploblastic animal, i.e. they are derived only from two embryonic germ layers, for example, ectoderm and endoderm.
iii. Level of organization: Sponges have the cellular level of the organization.
iv. Body wall: The body wall of a common sponge consists of three layers.
Also, the sponges are important from a scientific point of view because of their property of the unusual cellular organization, the ability they have to regenerate the lost parts, and also their biochemical features.
Therefore, the correct answer is option (A).

Note: Both asexual and sexual reproductions occur in the sponges. The asexual reproduction occurs by the budding and the gemmules. In freshwater and a few marine sponges, gemmules or internal buds are formed. The sponges are hermaphrodite. The fertilization is internal.