BIOLOGY [2 Mark Question Answer]

The characteristics of class Aves are:

1. The body is covered with feathers.
2. They have wings to aid flying
3. They have scales on legs.
4. They have no teeth.
5. They have jaws provided with home beaks

The bones of the birds are hollow and filled with large air cavities. This makes their skeleton light and enables them to fly. On the other hand, bones of other vertebrates are dense and solid and form a heavy skeleton.

The bones of birds have large air cavities (are hollow) and hence are light. This enables them to fly. On the other hand, bones of other vertebrates are dense and solid and form a  heavy skeleton.

Mammals are regarded as the most advanced animal because they are the most recently evolved vertebrates who have the most advanced, complex brain, are the only animals that produce milk for their young ones, and give birth to babies.

The most notable characteristic of birds that are not found in any other group of animals is the presence of feathers. They are the only animals on earth that have a backbone as well as feathers that cover their entire body.
Also, their skeleton is light as their bones have air cavities and are hollow. They also have beaks with no teeth.

Two characteristics of Mammals:

1. They are warm-blooded animals with hair on their body.
2. They give birth to babies and are the only animals that produce milk for nourishing their young ones.

Two characteristics of Reptiles :

1. They are land animals with dry scaly skin on the body.
2. They breathe through the lungs.

Two characteristics of Amphibians:

1. They are animals which can live both on land and in water.
2. They breathe through the lungs and skin.

Two characteristics of Birds:

1. They are warm-blooded animals with feathers on their body.
2. They have homy beak and do not have teeth.

Warm-blooded animals are those animals whose body temperature remains the same and is not affected by the temperature of their surroundings, e.g. Birds, Humans.
Cold-blooded animals change their body temperature with the change in the temperature of their surroundings, e.g. Fish, reptile

The animal is a mollusc because although both molluscs and cnidarians have soft bodies and tentacles only molluscs have shells (internal or external) and cnidarians don’t.

Annelids are invertebrates which include segmented worms. They are found in moist soil and pond water. They have a soft, cylindrical, and bilaterally symmetrical body. Their body surface is marked into ring-like compartments called segments that help in movement. They have a special organ of excretion called nephridia.
Examples: Leech and earthworm.