The indoor cabinet also typically includes a furnace (or the inside part of a heat pump). The indoor and outdoor units are connected by a refrigerant line. Greater energy efficiency possibilities - Split air conditioning systems have SEER ratings from 13 to 23.
A single gene trait is controlled by a single gene. Polygenic traits are controlled by two or more than two genes on different chromosomes. These genes are described as polygenes. Examples of human polygenic inheritance are height, skin color and weight.
Polygenic Traits. If you were to graph out a trait or phenotype that is polygenic, you would notice a trend. These traits have what's called continuous variation, showing a bell curve of values for the phenotype. This is because there are multiple genes that play a role in the phenotype, and each gene could have multiple alleles.