Question

study of external structural optimisation of any two animal out of cockroach,frog,fish,pigeon and rat

Answer 1

COCKROACH

Examine the body of a cockroach. You will find that it has 6 legs. Each leg has joints. A cockroach has two compound eyes. At the posterior end it has two anal cerci. The body is dorsoventrally flattened and is divided into 3 parts: head, thorax, and abdomen.

FISH

Examine a bony fish. Note the position of the eyes, shape of the mouth, scales on the body, fins on the dorsal and ventral surfaces. Also examine the shape of the tail fin. You can also feel the endoskeleton by grabbing it firmly.

The contour of the body is streamlined so that it can swim without much resistance. Fins also help in swimming. The gills are located just behind the head on the lateral sides. The gills are covered by an operculum. Gills enable the fish to obtain oxygen dissolved in water, and expel the carbon dioxide produced in the body.

The jointed legs make it a runner and its wings enable it to fly for a short distance. Note that the outer wings are leathery, but the inner ones are thin and membranous.

Hope it helps!!