Which is not a requirement for natural selection to occur?

The Hardy – Weinberg principle has seven conditions that should occur in the evolution of the population. One is when mutation does not happen. Two, is when natural selection is not occurring. Three, if the population is infinitely large. Four, if all the members of the population produce offspring.  Five, sexual intercourse is random. Six, the population will produce the same number of offspring. And lastly, the population does not migrate from one place into the other. The thing that would disrupt the genetic equilibrium is the mutation.

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.