A pair of genes that control a trait is referred to as an allele.
Answer:
B) soil animals plants
soil
Explanation:
Nitrogen is taken up by plant roots and combined into organic substances in the plant, such as enzymes, proteins and chlorophyll. ... Plant and animal wastes decompose, adding nitrogen to the soil. Bacteria in the soil convert those forms of nitrogen into forms plants can use. Plants use the nitrogen in the soil to grow.
The answer would be C, even though all of them are important for environmental health. Control of sexually transmitted diseases isn't ever talked about enough, especially with teenagers, and because of that, STD rates are on the rise and it's really sad.
