Which of the following is the unit of inheritance?

Mendel published his work on the inheritance of characters in $1865$,but it remained unrecognized until $1900$ because:
$(a)$ He could not provide any physical proof for the existence of factors.
$(b)$ His concept of factors as stable,discrete units that controlled the expression of traits did not find acceptance from his contemporaries.
$(c)$ Mendel's approach of using mathematics to explain biological phenomena was considered ahead of its time and unconventional.
$(d)$ Communication was not easy (as it is now),and his work could not be widely publicized.

Which of the following is a dominant trait of the garden pea plant?

How many pairs of contrasting traits were selected by Mendel for his study on garden peas?

Out of the seven pairs of contrasting traits studied by Mendel in pea plants,how many traits were based on color?

Give scientific reasons: The Mendelian experiments cannot be carried out in human beings.