DDT was used during second world war to control malaria among the troops and the civilians. Later, it was used as pesticide in agricultural and household practices. Due to its excessive use it entered into the food chain and its amount in the food crossed the permissible level. So, it was banned by United States.
Easy. Answer is oxygen because it says which one was missing before any life was on earth. And in order to have life on earth you need oxygen!
:)
Answer:
The answer is letter B
Explanation:
One species will take over most or all of the zone of overlap. Because there will be a competition between the two species. One wil thrive, while the other will eventually die out due to natural selection.
It is important to remind that according to the competitive exclusion principle, no two species can occupy the same niche.
