Not true, certain chemical transmitters stimulate certain receptors
For the first question the answer is D
For the second question the answer is B
This is parasitism because one organism (mosquito) is benefitting (by acquiring nutrition) and the other organism (human) is harmed (by the red itchy bump).
C. because if there was no clovers, the mice can not feed, and if the mice can not feed they will starve out and die.