How might the trait`s heritability affect the species` ability to undergo natural selection?

If it is almost impossible for a favorable trait to get passed down to offspring due to reproductive struggles, the species would not be able to undergo natural selection due to a lack in appearance of a trait.

Explanation:

If there are only two organisms with the adaptation, both of which lack any reproductive abilities, the odds of most of the species not dying out are very low. Only those two will have the adaptation and they rest will die out.

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