It means differences in DNA among individuals of the same species. It results from mutations, meiosis, and sexual reproduction. Consequently enable natural selection to act, helping populations evolve and adapt to environmental changes over generations. Without it, species would struggle to survive new diseases or climate shifts.

Inherited variation is passed through genes and includes traits like eye color or blood group. Environmental variation, however, comes from external factors like diet, climate, or lifestyle. For example, identical twins may grow to different heights if raised in different conditions. Often, both types (environmental and inherited) interact to shape final traits.

It involves traits with distinct categories, such as blood group (A, B, AB, or O). These traits are usually controlled by single genes and unaffected by the environment. Other examples include the ability to roll the tongue or attached earlobes. Such traits are easy to observe and genetically predictable.

It helps explain why people respond differently to diseases and treatments. Understanding genetic differences allows doctors to create personalized treatment plans and predict risks for inherited conditions. It also aids in vaccine development, drug dosing, and gene therapy—especially in cancer, rare disorders, and precision medicine.

No, mitosis produces identical cells for growth and repair. It doesn’t introduce any changes at DNA level. In contrast, meiosis introduces variation through crossing over and gamete fusion. This genetic reshuffling ensures that offspring are unique, which boosts adaptability and strengthens survival across generations.