Differences in characteristics observed between individuals of the same species is known as

Step 1: Analyze the question The question asks for the term used for differences in characteristics between individuals of the same species, for example height, skin colour, or blood group among humans.

Step 2: Explain the concept Look at what each option means:

• A. Trait: A single characteristic of an organism, such as eye colour. It describes one feature, not the differences between individuals.
• B. Phenotype: The observable physical expression of an organism's genes and environment. It describes how an individual looks or behaves, not the differences between individuals.
• C. Mutation: A sudden change in the genetic material (DNA or chromosomes). It is one possible cause of differences, not the name for the differences themselves.
• D. Variation: The differences in characteristics among individuals of the same species. This matches the question exactly.

Step 3: Solve Individuals of one species (for example, humans) differ in height, complexion, and fingerprints. These differences are called variation. Variation can be:

• Continuous, such as height, weight, and skin colour, which show a range of values.
• Discontinuous, such as blood groups and the ability to roll the tongue, which fall into distinct categories.

Step 4: Answer The correct answer is D. variation.

Exam tip: Remember the key phrase "differences within a species" means variation. If a question asks about a single feature, think trait. If it asks about a sudden genetic change, think mutation.