Diffusion is one form of passive transport that doesn't require the expenditure of cellular energy. A molecule can diffuse passively through the cell membrane if it's lipid-soluble, uncharged, and very small, or if a carrier molecule can assist it. ... The assisted process is known as facilitated diffusion.
Got this off google but still hope it helps :)
Answer:
similarities
Explanation:
The concept of reproductive isolation relates more toward genetic similarities to distinguish between species. The barriers prevent closely related species living in the same geographical area from interbreeding. They help to keep each species distinct from the others.
Yes Darwin’s theory of natural selection
Gravity is one reason but also it depends in the speed, if the wave is fast, it will go higher and then bend. hope i helped :D