Answer: 1. all cacti in the same area
Explanation: All saguaro cacti in the desert is considered a population because population is the number of organisms of the same specie that exist and live together in a particular geographic region at the same time, and also have the capability to interbreed within themselves.
I believe the answer is the Plateau phase of the sexual response cycle. The sexual response cycle has four stages of sexual responding described by Maters and Johnson; that is the excitement, plateau, orgasm, resolution phases. During the excitement phase, the genital areas become engorged with blood. During the orgasm phase, there are muscle contractions all over the body, further increasing breathing, pulse and blood pressure rates; and during resolution phase the body gradually returns to its unaroused state as the engorged genital blood vessels release accumulated blood.