The answer is B because continental climate is the combination of both hot and cold climates. The Earth isn't only dry nor is it only polar. It is a combination of both that make up the Earth as it is today.
In a food web there is a hierarchy, if any one of the parts of a food web is changed it can effect the parts above that may consume it, or the parts below that it may consume. Since the food web relies on balance and a hierarchy, if something changes it could disrupt the balance and flow of energy in the food web.
It’s C. Amino acids bind to CCA3’OH end of tRNA via ester bond.