In amphibians, sex of frogs can be distinguished with the presence of sound producing vocal sacs. These organs are present in males which make them crock lauder, than females, so as to attract females for mating.

Tadpole undergoes metamorphosis to form adult.

Metamers is the scientific term given to earthworm's body segments.

Smooth muscle fibres taper at both the ends (fusiform) and do not show striations. They are also called involuntary muscles.

The different cell junctions found in tissues are

(i) Tight junctions are regions where plasma membrane of adjacent epithelial cells are held close together. They check the movement of material between then.

(ii) Gap junctions are meant for chemical exchange between adjacent cells.

(iii) Adhering junctions perform connecting function to keep neighbouring cells together.