Answer:
In ecology, a biological interaction is the effect that a pair of organisms living together in a community have on each other. They can be either of the same species (intraspecific interactions), or of different species (interspecific interactions).
Explanation:
pa brainliest
The Miller-Urey experiment is important because this was considered as the breakthrough in the study of origin of life, as to where and how exactly life began on earth and that it was possible to form organic molecules from inorganic molecules.
D is the answer to the problem
Answer:
12
Explanation:
Suppose the four different strains are P, Q, R, S. Thus, the first infection can be from any of the four strains and it occurs in 4 ways.
Since an individual cannot be infected again with the strain from which he/she is been previously infected;
Then, at the second time;
The possible number of strain to be infected with = 4-1 = 3 ways
Thus; the number of possible different levels of severity can be viewed by forming two lettered word P, Q, R, and S without repetition which is:
= 4 × 3
= 12
