Natural selection is a consequence of

Step 1: Analyze the question The question asks what natural selection results from, that is, what must be present in a population for natural selection to happen.

Step 2: Explain the concept Natural selection is Darwin's mechanism of evolution. It works like this:

1. Variation: Individuals in a population differ in their traits (size, color, speed, disease resistance, etc.).
2. Struggle for existence: More offspring are produced than the environment can support, so there is competition for food, space and mates.
3. Survival of the fittest: Individuals with traits better suited to the environment survive and reproduce more.
4. Inheritance: These advantageous traits are passed to the next generation.

If all organisms in a population were identical, there would be nothing for nature to "select" between. Variation is therefore the raw material of natural selection.

Step 3: Check the options

• A. Distribution of organisms: This describes where organisms live. It does not cause selection.
• B. Adverse conditions: These are a selecting pressure (for example drought or disease). They act on variation but are not what natural selection arises from. Without variation, adverse conditions would just kill everyone equally.
• C. Variation in organisms: Correct. Differences among individuals let some survive better than others.
• D. Inbreeding: This reduces variation and is not the basis of natural selection.

Step 4: Answer The correct answer is C. variation in organisms.

Exam tip: Remember the chain V-S-I: Variation → Selection (survival of the fittest) → Inheritance. If a question asks what natural selection depends on or results from, think "variation" first.