Question

The diagram shows the process of fertilization in flowering plants. Observe it carefully and answer the questions.

Answer 1

This is the diagram of the pistil of a flowering plant. Here the fertilization takes place. It starts When the pollen reaches the pistil of the flowering plant it starts the process of the formation of the pollen tubes.

Complete answer:

Here in the question, the first answer is (a) the pollen grain, as in the diagram the small round structures are the pollen grains. Pollen grains are the small structures that are the male gametophytes that produce the male gametes.
The pollen grains generally have the hard coating which is made up of sporopollenin, whose main function is to save the pollen from the external factors which can lead to the damage of the pollen gametes.
It protects the pollen during the movements which are done from the stamens to the way to the pistil of the flowering plant. When this pollen reaches the pistil of the flowering plant it starts the process of the formation of the pollen tubes.
These pollen tubes help the sperm to reach the ovule which contains the female gametophyte.
Each pollen contains the vegetative and the generative cell. The second answer to this question is (b) stigma.
The third answer to this question is (c) ovary wall and the last answer to this question is (d) is the egg cell.

Note: The pollen grains are the minute body structures that have the varying shape and the structure, generally formed in the male structures of seed-bearing plants. And transported by the various means or can also be said as pollen agents. Stigma is the modified portion of the plant which has been adapted for the reception of pollen. It has a sticky surface. Ovules are being protected by the ovary walls of the plant. Egg cells are the tiny structures which have been embedded in the structure of the ovary in the base of the pistil.