In females,the period around $45-50$ years of age is known as:

Which among the following statements are true for unisexual flowers?
$(i)$ They possess both stamen and pistil
$(ii)$ They possess either stamen or pistil
$(iii)$ They exhibit cross pollination
$(iv)$ Unisexual flowers possessing only stamens cannot produce fruits

Length of pollen tube depends on the distance between :

The spherical bacteria of the species $Neisseria$ $gonorrhoeae$ are responsible for which sexually transmitted disease in humans?

$(i)$ $(a)$ Write the full form of $DNA$.
$(b)$ State the role of $DNA$ in the cell nucleus.
$(c)$ What will be the after-effect if the information of the $DNA$ is changed?
$(ii)$ Explain the importance of $DNA$ copying in reproduction.

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.