Question

match the traits with examples of how they influence the phenotype of an organism. epistasis environmental effects pleiotropy chickens will produce a \walnut comb\ on their head only if they possess at least one dominant allele in each of two different genes. fish will only grow colorful tails if no predators are present during development. a gene influences both the height of a tree and the number of branches that it produces.

Explanation:

Epistasis occurs when the expression of one gene is affected by one or more other genes. Here, chickens' "walnut comb" phenotype depends on dominant alleles in two different genes. Environmental effects are when environmental factors influence phenotype; fish growing colorful tails based on predator - presence is an environmental influence. Pleiotropy is when a single gene affects multiple traits; a gene influencing both tree height and number of branches is an example of pleiotropy.

Answer:

epistasis - Chickens will produce a "walnut comb" on their head only if they possess at least one dominant allele in each of two different genes.
environmental effects - Fish will only grow colorful tails if no predators are present during development.
pleiotropy - A gene influences both the height of a tree and the number of branches that it produces.