Question

The animal that can change its colour is
A. Planaria
B. Octopus
C. Leech
D. Hydra

Answer 1

Hint: The animal that can change its color belongs to class Cephalopoda of phylum Mollusca. Cephalopods have chromatophores in their skin which are specialized cells. Each chromatophore cell is filled with pigment, which can be red, yellow, brown, or black.

Complete answer:
Octopus belongs to class Cephalopoda of phylum Mollusca. Cephalopods have chromatophores in their skin which are specialized cells. Each chromatophore has pigment, which can be red, yellow, brown, or black, filled in a sac called cytoelastic succulus.
Octopus can change their color according to their activity or surroundings. When the muscles around the cell constrict, the pigment sac pulls wider, causing more pigment on the octopus skin. When the muscles loosen, the pigment sac shrinks backward, and less pigment is visible.
The expansion or contraction of each chromatophore cell attached to a nerve is controlled by the nervous system. When the octopus sees something, like a predator or prey the brain sends a signal to the chromatophores, which induces it to change color.
Also,
> Planaria: It belongs to the phylum Platyhelminthes. Its body is unsegmented.
> Leech: It belongs to the phylum Annelida. They have a segmented and soft body.
> Hydra: It belongs to the phylum cnidaria. They have a high regeneration ability.

The correct answer for the above question is option (B) which is an octopus.

Note:
The advantages of color-changing properties of octopus are:
> Mixing into the surroundings to avoid predators.
> Masking it’s identity, location or movement.
> The octopus changes its color and shapes to mislead the prey.