What are the benefits of using mechanical barriers during sexual act?

Which of the following is an artificial method of vegetative propagation?

Why do we need to adopt contraceptive measures?

In the diagram of the human male reproductive system given below:
$(a)$ Label parts $A$ and $B$.
$(b)$ Name the hormone produced by organ $X$. What is the role of this hormone in the human male?
$(c)$ Mention the name of substances that are transported by tubes:
$(i)$ $C$ and $(ii)$ $D$.

Why does bread mould grow profusely on a moist slice of bread rather than on a dry slice of bread?

$(a)$ Identify the organisms $A$ and $B$ and the mode of asexual reproduction exhibited by them.
$(b)$ How will an organism be benefitted if it reproduces through spores?
$(c)$ Mention the two asexual methods by which Hydra can reproduce. Explain briefly any one such method.