ICSE Class 8 Answered

Sunlight

• The energy obtained from sunlight is essential for the production of food by photosynthesis.

Air

• Oxygen from the air is essential to animals for respiration.
• Carbon dioxide is useful to plants for photosynthesis.
• Air serves as a medium for the flight of birds, insects etc.
• Air is an agent for the dispersal of seeds, fruits, flowers, pollen etc.

Water

• Water is used by plants and animals for drinking and various other purposes.
• Water is the chief constituent of protoplasm in cells.
• It is required for various biochemical reactions which occur in organisms.
• It helps to transport nutrients and excretory products in organisms.

Temperature

• Temperature affects the distribution of living organisms in the environment.
• It affects the enzymatic activities in organisms.
• Hot, mild or cold temperature influences the kind of body functions of plants and animals living in such areas.
• Most plants and animals survive between 10°C and 40°C.

Soil

• Soil provides the substratum for the growth of plants.
• It contains water and mineral nutrients such as sodium and potassium required by plants.
• Soil also provides a dwelling place for burrowing animals such as rats, snakes and earthworms which even swallow the mud containing dead organic matter.
• In deserts, soil provides support to plants such as prickly pear and date palms.
• Even water bodies have some soil at the bottom which is required by organisms living there.