Concept:Variation refers to the differences in characteristics seen among individuals of the same species.
Explanation:Individuals of the same species differ in features such as height, colour, or behaviour.
These observable or measurable differences are termed variation.
Variation can be caused by genetic factors, environmental factors, or both.
A trait is a single characteristic, phenotype is the physical expression of genes, and mutation is a change in genetic material.
Therefore, the correct term for differences between individuals of the same species is variation.
Answer:D. variation