Question

why are most chloroplasts on the underside of a leaf?
otherwise wind and environmental conditions could affect them
otherwise the chloroplasts will be too productive and harm the plant
otherwise the leaves would reflect all of the sunlight
otherwise the sun would burn the leaves

Explanation:

Chloroplasts are on the underside of leaves to be protected from harsh environmental factors like strong sunlight and wind - related damage. Excessive sunlight can harm the photosynthetic machinery in chloroplasts and wind can cause physical damage.

Answer:

otherwise wind and environmental conditions could affect them