Answer: An antigen
Explanation:
A molecule that evokes immune response in the body of an organism is known as antigen. These substance can be protein, carbohydrates, lipids when asked for chemical nature.
Physically these substance can be dust particles, smoke, pollen grains, some food particles. Antigen can be defined as the substance that tends to produce immune response by the immune system of the body.
Hence, the correct answer is option D
This scientific study revealed that predation is the dominant factor affecting prey population on cycling. Population cycles is the feature where populations rise and fall over a predictable period of time. For example there are some species where population numbers have reasonably predictable patterns of change. From the study depicted in the question; when snowshoe hares are scarce, many lynx leave their home range in search of food. An increased predation of the hare due to high populations of lynx and other predators increases the decline in the hare population.
