Mendel published his work on inheritance of characters in $1865$ but it remained unrecognised till $1900$ 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 the contemporaries

$(c)$ Mendel's approach of using mathematics to explain biological phenomena was totally old

$(d)$ Communication was not easy (as it is now)

The given diagram $A$ and $B$ indicates

A diseased man marries a normal woman. They get three daughters and five sons. All the daughters were diseased and sons were normal. The gene of this disease is

The average ratio of male to female individuals based on $XX$ and $XY$ type of sex determination, in total world of human population is

Animal which remains male initially, then changes to female $(Tapeworm\, proglottides)$ is called