When an allele fails to express itself in the presence of another allele, the former is said to be

Gregor Mendel conducted his hybridization experiments on garden peas for ......... years.

The modified allele could be responsible for the production of which of the following?

The method used to determine whether an individual is homozygous or heterozygous is known as:

In the case of $PTC$ tasters and non-tasters in humans,$T$ represents the dominant allele and $t$ represents the recessive allele. Which of the following genotypes is unable to taste $PTC$?

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