BIOLOGY [3 marks Question Answer]

Worms – Arthropods, Butterfly, Ascaris, Scorpion, Honey bee, Liverfluke, Leech, grasshopper, Eathworm
Molluscs – Snail
Fishes – Rohu
Amphibians – Toad, Frog
Reptiles – Snake, Lizard, Turtle
Birds – Parrot, Pigeon
Mammals – Rat, Bat, Dog, Cattle, Cow, Rabbit, Monkey, Elephant

Four characteristics of reptiles are :

1. They are cold-blooded vertebrates.
2. They have dry skin covered with scales.
3. They lay eggs that have leathery shells.
4. They breathe through the lungs.
   e. g.: Lizard, crocodile.

On the basis of food they eat, animals are classified as:

1. Herbivores – They eat only green plants as food. Examples: cow, goat, etc.
2. Carnivores – They eat only the flesh of other animals as food. Examples: tiger and lion, etc.
3. Omnivores – They eat both plants as well as the flesh of other animals as food.
   Examples: bear, crow, man, etc.

The exoskeleton is a tough outer covering of an animal body. e.g. Crab, lobster have exoskeletons.
Exoskeleton

1. It is a rigid external covering of the body that provides support and protection to the body.
2. It is present in invertebrates.
3. Examples: Crab, lobster, spiders, scorpions, etc.
4. It is in the form of a shell, or scales or feathers, etc.

Backbone

1. It is an internal skeleton (endoskeleton) that provides support and protection to the body.
2. It is a present invertebrate.
3. Examples: Humans, fish lions, dogs, etc.
4. It is made up of a number of vertebral joined to form a vertebral column.

Arthropods are invertebrates with jointed legs, a segmented body, and a bilaterally symmetrical body that is divided into head, thorax, and abdomen.
Anthropods are further classified into –

1. Arachnids – They have fused head and thorax, four pairs of legs, hard exoskeleton, no wings, and antennae. Examples: Scorpions and spiders.
2. Crustaceans – They have fused head and thorax, appendages on all segments, a variable number of jointed legs, and two pairs of antennae extending from the head. Examples: lobsters and sprimps.
3. Myriapods – Body divided into a large number of segments and have two pairs of legs per segment (example: millipede) or one pair of legs per segment (Example: centipede). The number of legs may vary from 20 to 200.
4. Insects – Their body is divided into head, thorax, and abdomen. They have three pairs of legs, two pairs of wings (some have one pair or none), and a pair of antennae. Examples: ants and butterflies.