Well, since its about it needing to survive and reproduce in a specific environment, it should be fitness.
Carbon is stored in the biosphere within living or recently dead plants, animals and microorganisms in the ocean and on land. Forests contain 86 percent of the planet's carbon on top of the ground. This biomass is released into the carbon cycle through natural decomposition and respiration.
Hi!
During protein synthesis,
introns are removed.
and
exons are joined.
So, B.