Page 81 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

6. Write adaptive features of:

(a) Camel (b) Polar bear
Ans. (a) Camel: The nostrils of a camel close to avoid sand getting into them. Their long

eyelashes keep the sand out of the eyes and thick eyebrows shield their eyes
from the hot Sun. Camel's ears are covered with hair, even on the inside. The

hair helps keep out sand or dust that might blow into their ears. Camels can

survive a week or more without water, and can live for several months without
food. It stores fat in the hump which helps it survive for long periods without

food and water. The hump decreases in size as the fat is used up. With proper
food and rest it returns to its normal size. Feet of camels are wide and padded,

so they can walk on the hot sand easily. They have thick lips to eat the prickly
desert plants without hurting themselves.

(b) Polar Bear: Polar bear adapts to its habitat by developing a layer of white fur

and fat under its skin helps to preserve body heat. White fur helps them to
blend with the snowy background and protects it from enemies. The claws of

the polar bear are curved inwards to help dig into the ice. Wide paws help it in
swimming and walking on the snow. They have very strong sense of smell which

helps to locate and catch prey. Polar bears can swim under water for long hours
by closing their nostrils.

7. Name and write about elements of weather.

Ans. Elements of Weather: The main factor which is responsible for all the changes in
the weather is the Sun. The other factors which influence weather are temperature,

rainfall, humidity and winds. These are called elements of weather. All these factors,
directly or indirectly are influenced, by the Sun.

• Temperature : Temperature can be defined as the measure of the degree of
hotness or coldness of an object. It varies over a period of day and night and

from one season to the other. In the afternoon, the temperature may be high,

but it may fall during the night. During the summer season, the temperature
increases. At some places on the Earth, it may reach close to 50°C. In winters,

the temperature drops and may reach below 0°. This variation is due to the
heating of the surface of the Earth by the Sun.

• Rainfall : In our country, rainfall depends mainly on monsoon rains. The
southwest monsoon (from June to September) brings heavy rain to many parts

of the country. The northwest monsoon (from November to March) brings light
rains.

81
81