Carbohydrates, proteins, fats and minerals are the most essential components of our diet, and they are collectively known as nutrients. Roughage refers to the fibrous part of our food like green leafy vegetables, salads, fruits, etc. Vitamins themselves are components of nutrients.   

Plants are photoautotrophs, which can make their own food by using carbon dioxide, water and minerals in the presence of sunlight and convert these inorganic substances into organic form.  

The process of having food and its utilization by the body is known as nutrition. Digestion is the process of breaking down of complex nutrients into simpler absorbable form. Assimilation refers to the process of using absorbed food nutrients to be incorporated (to build) into cytoplasm of the cell for its metabolism. Egestion refers to the elimination of water and undigested materials from the body.

Cytoplasm is a jelly-like substance which is present all around the nucleus in which cell organelles are placed. Cell membrane is the outer covering of a cell that separates the interior of all cells from the outside environment. Nuclear membrane is the membrane, which surrounds the central nucleus. Nucleoplasm is a jelly-like substance present in the nucleus. 

In cell, nucleus containing the hereditary materials is located in the centre. It is spherical in shape. Mitochondria, food vacuole and golgi body are the other cell organelles but they are not located in the centre.

Photosynthesis is the process of formation of food by green plants using inorganic raw materials. The products formed during the process are carbohydrates, i.e. glucose along with the release of oxygen. 

Green plants prepare their own food by using inorganic raw materials. This process takes place in the leaves containing chlorophyll, which is required for photosynthesis. Flowers are the organs of reproduction, fruits are the source of seeds for the next crop and thorns are the reduced leaves to prevent transpiration.

In parasitic mode of nutrition, the parasite lives in/on the body of the host and draws its nutrition from there.

Autotrophs are the living organisms, which make their own food by using inorganic raw materials. Heterotrophs are the organisms which depend on autotrophs for their nutrition requirements. Other organisms which use chemical energy are called chemoautotrophs. Host is that organism in/on the body of which another organism/parasite lives and draws its nutrition. 

Though plants act as a source of energy for all the heterotrophs, but even plants depend upon the energy of sun for the formation of their food. Therefore, sun is said to be the ultimate source of energy.

Autotrophs are the organisms, which make their own food by using inorganic raw materials. The word 'autotroph' is derived from two Greek words: autos means 'self' and trophe means 'nutrients/nourishment'.

Plants prepare their food by using energy from the sun. Thus, solar energy is the correct option.

Nitrogen is required by the plants in large amounts. During the plant growth, plant takes up nitrogen from the soil and makes the soil deficient.

Plants get nitrogen from the soil by the activity of bacteria present in their root nodules, which convert atmospheric nitrogen into usable form. 

In the humid weather, fungal growth is enhanced especially on the food products from which they can draw their nutrition.

Algae are slimy green organisms present in ponds. Moist forms of algae can perform photosynthesis and are thus, autotrophic. Saprotrophic nutrition is the mode of nutrition in which an organism lives on dead and decaying organic matter to draw nutrition. Therefore, it is an incorrect statement.

Pitcher plant is named so because in this plant, the leaves are modified to take up the shape of pitcher in order to trap the insects.

Rhizobium and leguminous plants share a mutual relation with each other, benefiting each other and getting benefited from each other and the relation is known as symbiotic relation.

Growth of fungus is increased with the moisture in the atmosphere, i.e. the amount of water vapours. Thus, rainy season is the best for the fungal growth. 

The carbohydrates, i.e. the glucose formed during photosynthesis in plants is converted to starch as an energy reserve.