1. Multicellular organisms like humans have large body size and hence diffusion pressure alone cannot carry oxygen to all body parts. Thus, they have respiratory pigment to take up oxygen from lungs to body parts.

    Multicellular organisms like humans have large body size and hence diffusion pressure alone cannot carry oxygen to all body parts. Thus, they have respiratory pigment to take up oxygen from lungs to body parts.

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  2. Carbon dioxide gas is essential for photosynthesis by plants- It is also a green-house gas (GHG). Upto 350 ppm (ppm = parts per million) concentration in the-atmosphere, CO₂ is both a good raw material as well as essential for keeping the Earth warm. However, when concentration of Co₂ rises (as presRead more

    Carbon dioxide gas is essential for photosynthesis by plants- It is also a green-house gas (GHG). Upto 350 ppm (ppm = parts per million) concentration in the-atmosphere, CO₂ is both a good raw material as well as essential for keeping the Earth warm. However, when concentration of Co₂ rises (as presently it is 387 ppm), it becomes a pollutant because it-results in global warming. The global warming is quite dangerous because it tends to melt polar ice and glaciers existing on mountains, raise in the water level of oceans and submerge severals coastal areas and islands.

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  3. sun plays an important role in weathering of rocks for soil formation. It heats up the rocks during the day. Heating causes the rocks to expand. During night, the rocks cool down and contract. Deferent parts of a rock expand and contract at different rates resulting in its cracking and breaking up iRead more

    sun plays an important role in weathering of rocks for soil formation. It heats up the rocks during the day. Heating causes the rocks to expand. During night, the rocks cool down and contract. Deferent parts of a rock expand and contract at different rates resulting in its cracking and breaking up into smaller pieces or fragments (boulders).

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  4. (i) Dust consists of suspended particles. The latter pass into nasal tract and cause a lot of discomfort including allergic asthma, bronchitis, cough and cold (ii) Dust reduces light intensity (iii) Dust particles are eye irritants. (iv) Dust particles settle over plant foliage and reduce photosynthRead more

    (i) Dust consists of suspended particles. The latter pass into nasal tract and cause a lot of discomfort including allergic asthma, bronchitis, cough and cold
    (ii) Dust reduces light intensity
    (iii) Dust particles are eye irritants.
    (iv) Dust particles settle over plant foliage and reduce photosynthetic activity
    (v) Dust particles block stomata reduces gaseous exchange in plants
    (vi) Dust particles can pick up toxic metals and chemicals being emitted by industries

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  5. Glass is transparent to sunlight allowing it heat waves do not escape from the car due I car placed in the sun will become very hot. to pass into the interior of the car. It heats up the interior. But to glass being opaque to the same. As a result, the interior of the It is similar to glass house efRead more

    Glass is transparent to sunlight allowing it heat waves do not escape from the car due I car placed in the sun will become very hot. to pass into the interior of the car. It heats up the interior. But to glass being opaque to the same. As a result, the interior of the It is similar to glass house effect.

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