Final answer:
The word 'diversity' matches the concept of variation in biology, referring to the genetic differences and resulting phenotypic diversity within a population. Examples include various fur patterns in dogs and sexual dimorphism in birds.
Step-by-step explanation:
The word that matches variation is 'diversity'. Variation, in a biological context, refers to the differences seen within a population. Each organism within a population will have genetic differences that contribute to the population's overall diversity. These differences can be in phenotypes, which are observable traits, or genotypes, which are the genetic make-up.
Population variation can be seen in many forms. An example is the multitude of fur colors and patterns found in domestic dogs. This is a direct consequence of the genetic variance present in the dog population, where diverse alleles result in different phenotypes.
When discussing sexual dimorphism, this refers to the differences in appearance or behavior between males and females of a species, often a result of sexual selection. For instance, in many bird species, males have more vibrant plumage compared to females, which can be a factor in mate attraction.