How many kinds of genotypes are possible in F₂, if four genes are segregating independently? 

When four genes are segregating independently in the F₂ generation, the total number of possible genotypes can be calculated by taking 2 to the power of the number of gene pairs. For each gene pair, there are 3 possible genotypes (assuming a simple dominant/recessive model - homozygous dominant, heterozygous, homozygous recessive). Therefore, the total number of genotypes for four independently segregating genes is  34 = 81 Hence, the correct answer is (2) 81.