Answer:
A mixture is a physical combination of substances thus it only requires physical processes to separate.
Answer:
D.
Explanation:
Although all of these answers are similar, it seems that all three are the answer. I am sorry if the answer ends up being B but I'm pretty sure the answer is D. Charles Darwin's evolution theory "evolved", get it, from the natural selection theory. The theory is described as "the process whereby organisms better adapted to their environment tend to survive and produce more offspring." However, some factors that effect natural selection are competition, selection and variation. I believe all three fit the answer and therefore I believe answer D is correct.
fourth period
The third period is similar to the second, except the 3s and 3p sublevels are being filled. Because the 3d sublevel does not fill until after the 4s sublevel, the fourth period contains 18 elements, due to the 10 additional electrons that can be accommodated by the 3d orbitals.
