Read the passage and answer the following questions :

The Green Revolution successfully increased food production by threefold, but it still couldn't meet the demand of the growing human population. The increased yields were primarily attributed to the use of improved crop varieties, better management practices, and the application of agrochemicals such as fertilizers and pesticides. However, farmers in the developing world often find agrochemicals too expensive, and further improvements in yield using conventional breeding methods become challenging.To address the limitations of traditional breeding techniques, scientists developed a technology called tissue culture. Tissue culture involves the regeneration of whole plants from small plant parts (explants) that are grown in a controlled environment, such as a test tube, with specific nutrient media. This ability of explants to regenerate into whole plants is known as totipotency. The nutrient medium used in tissue culture contains carbon sources like sucrose, inorganic salts, vitamins, amino acids, and growth regulators like auxins and cytokinins. By utilizing tissue culture techniques, a large number of plants can be propagated rapidly and efficiently, a process known as micro-propagation. These plants are genetically identical to the original plant from which the explants were obtained, making them somaclones. Many important food plants, such as tomato, banana, and apple, have been commercially produced using tissue culture. Another significant application of tissue culture is the recovery of healthy plants from diseased ones. Even if a plant is infected with a virus, the meristem (apical and axillary) regions remain free of the virus. Scientists can remove the virus-free meristem and grow it in vitro to obtain virus-free plants

Tissue culture refers to:

Regeneration of whole plants from explants under sterile conditions in nutrient media

The correct answer is Option (3) - Regeneration of whole plants from explants under sterile conditions in nutrient media

Explanation:

Tissue culture is a laboratory technique used in plant biology and agriculture for the regeneration of whole plants from small plant parts, known as explants, under sterile conditions in a nutrient-rich growth medium. The process involves the manipulation of plant cells or tissues in a controlled environment to stimulate their growth and development into complete plants.

The explants can be derived from various plant parts, such as leaves, stems, roots, or even single cells, and are carefully placed in a culture medium containing essential nutrients, vitamins, amino acids, and growth regulators like auxins and cytokinins. These components facilitate cell division, organogenesis, and differentiation, leading to the formation of new shoots, roots, and eventually, complete plantlets.

The capacity of a cell or explant to give rise to a whole plant is known as totipotency. This unique property allows cells to revert to a pluripotent state, capable of differentiating into various cell types and tissues.

Tissue culture has diverse applications in plant biotechnology, including the mass production of elite plant varieties (micro-propagation) with desirable traits, the production of genetically identical plants (somaclones), and the development of disease-free plants by culturing meristems (apical and axillary regions) free of pathogens. It has significantly contributed to advancements in plant breeding, conservation of endangered species, and the study of plant physiology and genetics.