In the process of grafting,what is the name given to the part of the plant that is attached to the cut stem of another plant?

Explain the term "Regeneration" as used in relation to reproduction of organisms. Describe briefly how regeneration is carried out in multicellular organisms like $Hydra$.

Differentiate between pollen grain and ovule.

Which of the following is a characteristic of asexual reproduction?

Give the respective scientific terms used for studying:
$(i)$ The mechanism by which variations are created and inherited,and
$(ii)$ The development of new types of organisms from existing ones.

The correct sequence of organs in the male reproductive system for the transport of sperms is: