Question

Regeneration ability of sponges is due to
(a)Reduction bodies
(b)Gemmules
(c)Archaeocytes
(d)Germ cells

Answer 1

Hint: Sponges contain primitive unspecialized cells that can undergo transformation into various cell types as the need arises. The cells are suspended in the mesohyl and dynamically travel between the mesohyl and cellular layers.

Complete answer:
Archaeocytes also known as amoebocytes are amoeboid cells present in sponges. They contain totipotency which is an ability to transform into sclerocytes, spongocytes, or collencytes. Archaeocytes along with other sponge cells including collencytes and structural elements, called spicules.
The archaeocytes are scattered in the mesohyl, having extraordinary potential for transformation into other types of cells, peculiarly observed in the Demospongiae. Some keep on their unspecialized type and reproduce during the life of the sponge, thus creating an embryonic stock in order to derive the cells as and when needed: rest of them get specialized to carry out peculiar activities. The cytoplasm of Archaeocytes contains abundant amounts of ribonucleic acid (RNA), and nuclei contain small nucleoli. Amoebocytes function in regeneration and in the transportation of food particles acquired at the choanocytes throughout the body of the sponge. Pigmented amoebocytes containing carotenoids and melanin confer various colors to the sponge.

Additional Information: The regenerative capacity of sponges is so extensive that it can regenerate not only by the restoration of body parts but can even form a whole organism from a single cell or fragment of tissues.
When exposed to unfavorable environments, sponges get reduced into small fragments that may sometimes even consist only of masses of archaeocytes covered by layers of pinacocytes. When the conditions revert back to normal, a complete sponge is regenerated from this fragment.
So, The correct answer is 'Archaeocytes'

Note: -Totipotency is defined as an ability to undergo differentiation into a number of cells that are very unlike each other but in the same organism.
-Zygotes are the only totipotent cells in humans which can be specialized into any cell and also give rise to a whole human form.