In parasitism, one organism harms another organism (the host). An example would be fleas living in cats/dogs; they feed on their blood.
Therefore the answer is A is harmed, and B is helped.
Thrifty metabolism
Thrifty metabolism is the genetic
tendency toward efficient use of energy that results in below-average energy
requirements and increased storage of calories as fat. Thrifty metabolism
contributes to less weight lost when an obese person reduce the amount of his
calorie intake even though there is changes in metabolism.
Next, Mendel took the F1 progeny and allowed them to self-fertilize. In the resulting F2 generation, 3/4 showed the dominant phenotype, and 1/4 showed the recessive phenotype. ... 1 out of 3 round pea plants from the F2 generation were true-breeding and produced only offspring with round peas.
could use less heat and air conditioning, lighting, electronics in our homes. Drive gasoline cars less often, and walk more. stop buying new clothes as much, and recycling used. use renewable energy sources like wind and solar power.