If b is a recessive gene list the offspring that will exhibit a short recessive trait

When a trait is recessive, an individual must have two copies of a recessive allele to express the trait. Recessive alleles are denoted by a lowercase letter (a versus A). Only individuals with an as phenotype will express a recessive trait; therefore, offspring must receive one recessive allele from each parent to exhibit a recessive trait.

Explanation:

One example of a recessive inherited trait is a smooth chin, as opposed to a dominant cleft chin. Let (S) represent the dominant allele, and (s) represent the recessive allele. Only (SS) individuals will express a smooth chin. To determine the probability of inheritance of a smooth chin (or any other recessive trait), the phenotype of the parents must be considered. If one parent is heterogeneous (SS) and the other is homologous recessive (SS), then half of their offspring will have a smooth chin

it is a limiting nutrient limited by a single nutrient in the ecosystem, & the single goes very slow.