The integumentary glands of mammals are
Sweat, sebaceous, scent glands and mammary glands. Mammary glands are the modified integumentary glands.

i) Forelimbs of birds are modified into wings with feathers for flight.
ii) The hind limbs are adapted for walking perching or swimming.

On the basis of position of notochord, the different prochordates are classified as follows.
1. Sub-phylum Hemichordata : The notochord is persistent as the stomochord in the anterior region of the animal. e.g., Balanoglossus.
2. Sub-phylum - Cephalochordata : The persistent notochord extends forward beyond the brain. e.g., Amphioxus.
3. Sub-phylum - Urochordata : The notochord is confined to the tail region of the larva, e.g., Ascidian.

Reproductive characters of mammals differ from those of Aves by
1. The presence of mammary glands.
2. Testes lie outside the body cavity enclosed in scrotal sacs.
3. Alecithal eggs.
4. Fertilization is always internal.
5. They give birth to young ones and feed their young ones with milk.
6. Placenta is a characteristic feature of mammals.

Aquatic habits of amphibians:
1. The larva of amphibians (tadpole) lives in water and breathes with gills.
2. External fertilization occurs in frog with water as a medium of fertilization.
3. The adult frog has webbed feet to swim in water
4. The skin is moist and glandular which helps in Respiration.
Terrestrial habits of amphibians:
1. The adult live on land and breathe through lungs. Bucco-Pharynx also helps in respiration.
2. The fore limbs are short and help to hop on land.

1. Fishes are poikilothermic, aquatic vertebrate with jaw.
2. Body is streamlined and differentiated into head, trunk, and tail.
3. Locomotion is by paired and median fins.
4. Body has covering of scales.
5. Respiration is performed by gills. Gill slits are 5-7 pairs.

The body wall is of two layers of cells namely the outer ectoderm and the inner endoderm, which is separated from each other by a non-cellular jelly-like substance called mesoglea.

This animals are characterized by the possession of a body cavity called coelom. Some animals of annelids have movable bristles called setae it is used to locomotion. Nephridia is the excretory structures and help to remove metabolic waste. They have central nervous system with a brain.