 It is useful to distinguish between the following terms. The terms heredity and hereditary will be used henceforth to refer to reliable resemblance relations between parents and offspring. Particular traits (phenotypic or genotypic) may be hereditary in this  sense.[1]  The term inheritance will be used to refer to causal processes of transmission between parents and offspring that account for heredity, and the mechanisms responsible for them. We might, for example, say that eye color is hereditary, and that genetic inheritance accounts for the heredity of eye color (or, more formally, for the heredity of variations in eye color). Multiple inheritance processes may be implicated in the heredity of a particular phenotypic trait. Inheritance is often construed as transmission of information, though this notion raises difficulties; this issue is discussed in  section 2.4.