Draw a diagram showing germination of pollen on stigma of a flower and label pollen grain, male germ-cells, pollen tube and female germ-cell in that diagram.

• Part that produces pollen grain
• Part that transfers male gametes to the female gametes
• Part that is sticky to trap the pollen grain
• Part that develops into a fruit.

During adolescence, several changes occur in the human body. Mark one change not associated with sexual maturation in boys.