Which of the following is not an artificial vegetative propagation?

State whether the following statement is true or false: Fertilization takes place in the ovaries.

Give two examples each of the following:
$(a)$ Plants having unisexual flowers
$(b)$ Agents of pollination
$(c)$ Physical changes on puberty that are common to both boys and girls.

$(a)$ List two reasons for the appearance of variations among the progeny formed by sexual reproduction.
$(b)$ $(i)$ Name the part marked '$A$' in the diagram.
$(ii)$ How does '$A$' reach part '$B$'?
$(iii)$ State the importance of the part '$C$'.
$(iv)$ What happens to the part marked '$D$' after fertilisation is over?

What is the main cause of variations among organisms during sexual reproduction?

Why are the testes located outside the abdominal cavity? Mention the endocrine and exocrine function of the testes.