Science [2 Mark Questions]

Difference between movement of leaves of sensitive plants and movement of shoot towards light:

Movement of leaves of sensitive plant	Movement of shoot towards light
(i) Growth is not involved.	(i) Growth is involved.
(ii) Movement is away from the source of stimulus (touch).	(ii) Movement is towards the source of stimulus (light).

a. It shields the earth from the harmful ultraviolet (UV) radiations from the sun.
b. - By the action of UV radiations on oxygen molecule which splits to form free oxygen atoms.
- These free oxygen atoms combine with oxygen molecule to form ozone.
c. The compound responsible for ozone depletion is chlorofluorocarbons (CFCs), along with other halogenated compounds such as halons and bromine-containing compounds.

If microrganisms are removed from the earth's environment then there would be dead bodies of plants and animals all around the Earth making it a difficult place to live in, more and more environmental pollution will pile up and accumalate. Moreover, the nutrient cycle will be stopped in the environment which will disturb the ecological balance.

Sexual reproduction takes place with the help of fusion of male and female gametes, thus 2 haploid gametes restore the diploid nucleus and thus form zygote, which have content from both the parent and hence producing a new recombination Whereas, in asexual reproduction the offspring develops from a single parent, the genetic material of the offspring is exact copy of the single parent.
Better chances of survival are seen in sexually reproducing organisms. This is because variation occurs in sexual reproduction which improves the vigour and vitality of the individual. This is helpful for the organisms in better adaptability to the environment.