Q. Why is the variation beneficial to the species but not necessarily for the individual?

Solution :

The reason why the variation is beneficial to the species rather than individuals is that sometimes the climatic changes have a drastic effect on the species, which makes their survival difficult. For example, if the temperature of the water body increases, there might be certain species of microorganisms might die. This may result in a disturbance in the environment. So, variation is beneficial to species and not to the individuals.