(a) This process is called crop-rotation.
(b) Mineral content of soil will be restored.
(c) Ashish is sincere, observant and interested in applying his knowledge to situations.

(a) Fungus are non-green plants that grow on dead and decaying matter for their food.
(b) Fungus are also useful as it can cure different type of infections.
(c) Vivek is sincere, curious and knowledge with a keen sense of applying it where necessary.

(a) The figure is of the stomata on a leaf.
(A)Guard cell
(B)Stomata
(b) The position showed in the figure is of closed stomata.

True, because photosynthesis is important for the existence of life on the earth. Photosynthesis is important process as it is provides food to all living organisms and maintains CO₂ - O₂ balance of nature.

Yes, plants having deep red, violet or brown coloured leaves can also carry out photosynthesis because they contain chlorophyll. But their green o colour of chlorophyll is masked by the large amount of all other coloured pigments.

Water and minerals are transported to the leaves by the vessels which run like pipes throughout the root, stem, branches and the leaves. These vessels are xylem and phloem, forming a continuous path or passage for the nutrients to make them reach the leaf.

Roots of pulses (leguminous plants) have a symbiotic association with a bacterium called Rhizobium. This bacteria convert gaseous nitrogen of air into water soluble nitrogen compounds and give them to the leguminous plants for their growth. Hence, farmers need not use nitrogenous tertilisers.

Labelled figure is given below:

Carbohydrates in wheat dough encourage the growth of yeast and other saprophytic fungi which breakdown carbohydrates into simpler compounds like CO₂ and alcohol and emit a foul smell.

Green plants are the source of energy for all the living organisms so that they can perform their normal functions. If all green plants and trees disappear, all the organism depending on them for food and shelter will also die.
The lack of gaseous exchange will lead to increase in amount of CO₂, causing death in humans and other animals also. The cycle of life will gradually disappear.

Plants show two major modes of nutrition, i.e.
(i) Autotrophs are those which can synthesise their own food.
(ii) Heterotrophs are those which are dependent on other plants and animals for their food.
They are of following types:
(a) Parasites, e.g. Cuscuta
(b) Saprotrophs, e.g. fungi

The following sketch shows that the plants are the ultimate source of food.

The presence of starch, a carbohydrate in leaves can be tested by iodine test. Iodine turns starch solution into blue-black colour. Pour few drops of dilute iodine solution on a boiled leaf. The leaf becomes blue-black in colour which proves the presence of starch in it.

Differences between parasites and saprotrophs

The organisms need to take food to build their bodies, to grow, to repair damaged part of their bodies and to obtain the energy to carry out life processes. Food provide resistance to fight against diseases and protection from different infections.