Homework Assignment 46 | Class 7 BBC Compacta Solutions PDF Download

1 (a) Cubs of the polar bear are born blind.

1 (b) The whole family stays in a den when the cubs are born.

1 (c) When her cubs weigh about 10 to 15 kg, the mother breaks the entrance to the den.

1 (d) The family spends time nearby outside the den for about 12 to 15 days.

1 (e) A fully grown elephant may stand four metres high.

1 (f) The Indian elephant is more easily tamed and trained than the African one.

2 (a) Of all the land animals, the elephant is the most intelligent and the largest.

2 (b) In some ways, the elephant is the most powerful animal.

3 (a) Snakes are covered with scales of various colours.

3 (b) The snake is one reptile that has no legs.

3 (c) It has very strong muscles that help it move.

3 (d) Other animals move quite slowly compared to snakes.

3 (e) The snake has a long forked tongue and uses it to smell things.

4 (a) All the other colours can be produced by mixing the primary colours.

4 (b) The primary colours in paints and printing inks are blue, red, and yellow.

4 (c) The primary colours of light are different—red, blue, and green.

4 (d) Using these three colours, all the other colours can be obtained.

5 (a) A mineral is a substance that is found in nature.

5 (b) It is made up of substances that were never alive.

5 (c) It has the same chemical makeup wherever it is found.

5 (d) The atoms of a mineral are arranged in a regular pattern and form solid units called crystals.

6 (a) Thermal expansion of ocean water because of warming raises the global sea level.

6 (b) The health of corals is jeopardised by warm waters.

6 (c) Ocean warming is a serious risk to food security.