Question

why the variation is necessary for the species but not for the individual​

Answer 1

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The variation is important and beneficial for species as it allows a species to adapt to a changing environment. Only those who adopt the changes can survive in harsher conditions by adapting to the changes. For an individual, the variation doesn't matter in most of the conditions.

Answer 2

Answer:

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