Sun is a huge sphere of hot gases burning at a very high temperature. The distance of the sun from us is very much. Even then the energy sent out by the sun is very large in amount. So, sun is the primary source of energy that causes change in the weather. Energy absorbed and reflected by the Earth's surface, oceans and atmosphere play an important role in determining the weather at any place.

Adaptive features of a polar bear that help in keeping it warm are as follows
(i) They have two thick layers of white fur.
(ii) They have layer of fat under their skin.

Difference between weather and climate

Polar regions Polar bear/penguin/ reindeer/musk oxen.
Tropical rainforests Red-eyed frog /elephants lion-tailed macaque/ lion and tiger.

Weather changes frequently in a very short period of time.

The maximum temperature of the day occurs generally in the afternoon while the minimum temperature occurs generally in the early morning.

Weather is a complex phenomenon which can vary over a short period of time and thus it is difficult to predict the weather of a place while it is easier to predict climate as it is the average weather pattern taken for a long time.

Tropical rainforest is found in India and central America.

Sun provides light as well as heat on the earth.

Those animals that can live both in water and on land are called amphibian, e.g. frog.

The major factor which determines the climate of a place is latitude.

Adaptation is the term used to describe such ability. Animals are adapted to survive in the conditions in which they live. So, fish dies when taken out of water while wall lizard dies if kept under water.

We use umbrella or raincoat to protect ourselves from rainwater during rainy season.

To escape the harsh winter conditions of polar regions birds travel to warmer place in winter. This movement of birds is termed migration. During migration the birds fly high where wind flow is helpful and the cold conditions allow them to disperse the heat generated by their flight muscles. How these birds travel to the same place year after year is still a mystery. These birds have built in sense of direction and they know which direction to travel. Many birds are guided by sun during day and by stars during night. Some ornithologists suggest that the birds may use magnetic field of the earth to find the direction.

(i) It has a big trunk which is used for two purposes-as a nose and for picking up food.
(ii) Its tusk can tear bark of trees. The elephant thus does not face problem as far as availability of food is concerned.
(iii) It has large ears which can hear small sounds. The large ears also help the elephant to remain cool in the hot and humid climate of the rainforest.