An ecosystem would best be described as a geographical area

where only plants live.
where plants, animals, landscape and climate all interact.
where plants, animals, landscape and climate are all independent of each other.
where organisms are independent of each other.

the answer to your question is:

c. complementary base-pairing

if, i suppose that a bee stings me swinging my hand away from a bee. then that if, i persist patient when a bee or wasp areas on your surface to investigate a scent or to take h2o and i secreting heavily, the bug ultimately will move of its personal agreement. if i don't need to set for it to disappear, lightly and gently wipe it off with a part of the paper.