LIFE SCIENCE

Detailed explanation-1: -It is necessary for the survival of species as only then will the species have the adaptability to survive in rapidly changing external conditions. Any variation which is suitable for the particular niche is selected by nature during its process of evolution. This is spread over several generations.

Detailed explanation-2: -A genetically diverse population of individuals is more likely to survive than a population of individuals with similar genetic makeup. Variation allows some individuals within a population to adapt to the changing environment and natural selection allows the expression of those beneficial traits to persist.

Detailed explanation-3: -Some variations make an individual better suited to survive and reproduce in their environment. If this continues over generations, these favorable adaptations (the heritable features that aid survival and reproduction) will become more and more common in the population.