The correct answer would be nuclear energy. The other answers would be fossil fuels because they are naturally made.
Answer:
Viruses and bacteria helps to build up our immune system, specifically our adaptive immune response such that we will be able to eliminate such pathogens when our body comes into contact with them. This builds up the resilience of our immune system over time, similar to how vaccines work.
OA) sugars and phosphates; nitrogen bases
Answer:
Energy decreases as it moves up trophic levels because energy is lost as metabolic heat when organisms from one trophic level are consumed by organisms of the next level. More specifically, 90% of metabolic energy is used, so only 10% will be passed down to the next level.