Correct the sequence of the following steps to describe the process of fertilization in plants.

1. The pollen grain begins to grow a pollen tube.
2. The pollen grain is deposited on the stigma.
3. The pollen tube grows down through the style to the ovary.
4. The fusion of the male gamete with the female gamete occurs inside an ovule.
5. A male gamete travels down each pollen tube.
6. The nucleus of pollen tube divides to form male gametes.

The diagram illustrates the structure of a flower.

1. Identify the parts labelled a to e.
2. Which part produces pollen grains?
3. Which part receives pollen grains for pollination?

To produce a new variety of crop plant with desired characteristics, artificial pollination is required. Why?

Most insect-pollinated flowers produce nectar and are sweet-smelling. Why?