State whether the following statement is true or false: The uterus opens into the vagina through the cervix.

$(a)$ Name the parts labelled as $A, B, C$ and $D$ in the diagram given below:
$(b)$ What is pollination? State its significance.
$(c)$ How does fertilization occur in flowers? Name the parts of the flower that develop into $(i)$ seed,and $(ii)$ fruit after fertilization.

Write true or false for the statement: If the egg is not fertilized,it lives for about one day.

What are sexually transmitted diseases? Name an $STD$ which damages the immune system of the human body.

Which of the following statements are true for flowers?
$(i)$ Flowers are always bisexual
$(ii)$ They are the sexual reproductive organs
$(iii)$ They are produced in all groups of plants
$(iv)$ After fertilisation they give rise to fruits

What is the effect of $DNA$ copying,which is not perfectly accurate,on the reproduction process? How does the amount of $DNA$ remain constant though each new generation is a combination of $DNA$ copies of two individuals?