When traits inherited from both parents are expressed, the alleles are said to have a. homozygous recessive alleles. b. polygenic inheritance. c. incomplete dominance. d. mutations.

B. polygenic inheritance.

Explanation:

Polygenic inheritance occurs when several pairs of genes interact to determine a trait, each with an additive effect on the other. That is, in this type of inheritance the characteristics of both parents are expressed in the offspring. Thanks to this type of interaction there is a very wide variety of phenotypes and genotypes for some characteristics. The interaction of these phenotypes with the environment further increases this variation, such as skin color and height, etc.

poor water quality affects most estuarine organisms, including commercially important fish and shellfish. the pollutants that have the greatest impact on the health of estuaries include toxic substances like chemicals and heavy metals, nutrient pollution (or eutrophication), and pathogens such as bacteria or viruses.