What is variation due to?GenderGenes and environmentGenes onlyEnvironment only

Variation is due to both genes and the environment. Here's a step-by-step explanation:

1. Genes: Every individual inherits genes from their parents, which play a significant role in determining their physical and biological characteristics. This is known as genetic variation. For example, eye color, hair color, height, and susceptibility to certain diseases are all influenced by genes.

2. Environment: The environment in which an individual lives and grows can also cause variations. This is known as environmental variation. For example, exposure to sunlight can affect skin color, and nutrition can affect height and weight.

3. Interaction of Genes and Environment: Often, it's the interaction between genes and the environment that leads to variation. For example, a person might have a genetic predisposition to being tall, but if they don't receive proper nutrition during their growth years, they might not reach their potential height.

So, variation is not due to just one factor, but a combination of both genes and the environment.