If after several rounds of artificial selection all alleles affecting the trait are fixed or lost, the narrow-sense heritability (h^{2}) of a trait is

h^2 = 0

Explanation:

When trait variance is a result of additive genetic factors, it is referred to as 'narrow sense heritability' or h^2. This estimate falls within a range of 0 to 1. h^2 is significant in indicating the evolutionary potential of a certain trait under study. Heritability value close to zero means that the variation in that trait is predominantly a result of environmental factors.

meiosis is the correct answer