When it comes to the heritability of vision in some african communities according to your text: ?

I believe the answer is: it is close to 0 due to vitamin A deficiency in their diet

The city provided various ways to handle vision defects, ranging from contact lenses, Glasses, lasers, etc. While the African communities have to suffer because of the lack of treatment (which will negatively affect them during hunting in particular)

It is close to zero due to vitamin A deficiency in their diet.

Explanation:

Vitamin A deficiency (VAD)  it is usual among the poor because it appears on those whose diets are based principally on rice or other carbohydrate-rich, micronutrient-poor calory providers. VAD is prevalent especially in Southeast Asia and Africa. Actually, the most problematic micronutrient deficiencies known are those that emerge as a consequence of low dietary consumption of iron, vitamin A, zinc, and iodine.

answer; the basal forebrain;