I believe it was The Continental Drift Theory , i could be wrong
The answer is A. Competition
is the contest for limited resources by
two populations of between individuals of
a population. Some populations adopt resource partitioning to reduce the stiff competition and mitigate the
disadvantages interaction leading to
coexistence of competing populations.

1) Fine flour and lumpy flour - B) Sieving
2) Mixed nuts - A) Handpicking
3) Sand and gravel - B) Sieving
4) Sand and palay - B) Sieving
5) Scrap iron and nail - C) Using magnet
(mark me brainliest if you're satisfied with my answer :))

Vitamin A deficiency is the leading cause of preventable blindness in children.