In genetics,the use of a checkerboard was introduced by

.......... is the unit of inheritance.

Which of the following traits of garden pea studied by Mendel is a recessive trait?

$A$ disease is caused by a dominant gene,but it shows only $20\%$ penetrance. $A$ heterozygous man marries a homozygous normal woman. What proportion of the children in the population is expected to have the disease?

$A$ cross in which an organism showing a dominant phenotype is crossed with the recessive parent in order to know its genotype is called

$A$ cross between a recessive parent and an $F_1$ hybrid is known as: