(a) What is tissue culture?
(b) Name any four types of ornamental plants which are being produced by the tissue culture technique.
(c) What is the importance of DNA copying in reproduction? Explain with an example.
(d) How does reproduction help in providing stability to populations of species?
(e) Why is variation during reproduction beneficial to the species but not necessarily for the individual?

(a) Tissue culture is the process of propagating new plants from a small piece of a plant's tissue, obtained from the growing tip of that plant in a suitable growth medium.

(b) Orchids, Dahlia, Carnation and Chrysanthemum are propagated by the method of tissue culture.

(c) DNA copying refers to the replication of DNA at the time of cell division. It is important for the transfer of genes of a parent(s) to the next species of the same kind. This ensures continuity of existence of a species. It also plays a very important role in giving rise to slight variations in offsprings, specifically important in the organisms that reproduce asexually as, in such organisms, only one parent is involved as there is no other source of variation in the DNA of the progeny from the parent. 

Example: Suppose there are some species of bacteria that are able to survive in suitable water at some temperature. Now, if the temperature of the water changes, and it increases, due to climate change, the species of bacteria can die and become extinct, but this would only happen if they were all identical. But this does not happen in nature as there is always some change or variations in DNA replication because it occurs through a biochemical process which is not accurate. So, due to this little variation in their DNA, some species of bacteria will be capable of surviving in warmer water, thereby ensuring the continuity of species. This is how DNA copying in reproduction is important

(d) Reproduction ensures that new offsprings are produced continuously to replace the dying individuals of the population. Thus, it ensures continuity of life and provides stability to the population.

(e) Variation during reproduction ensures that a species can survive and flourish even in adverse conditions. Thus, it is beneficial to the species but not necessarily for an individual.