There are five classes of food, out of this five only two provides energy; these are carbohydrate and fat and oil. Out of these two, carbohydrate provides the most energy for the body in the shortest time. This is the reason why glucose, which is the end product of carbohydrate is normally given to sport men during games.
Answer:
Natural selection can be described as a phenomenon in which individuals of a population which are better adapted to survive in an environment are favored by nature as compared to the individuals of the population which lack better characteristics to survive in the environment.
Through natural selection, evolution occurs and the allelic frequency changes over a period of time. The process of evolution as well as change in the allelic frequencies does not occur just by a single individual, rather it is a collective effort which takes a lot of time. Hence, we say that natural selection changes the population and not a single individual.
