The answer is C. Pheromones are hormones (which are proteinous) produces by individuals of the same species and are a means to send communication signals for social interactions. They signal alarm, food and even sex. Sex pheromones are released by females beetles into the environment to signal their availability for mating. The pheromones are picked up by receptors on the male beetles and this is how they find the females.
1. Acceleration of impulse
2. Deceleration of impulse
<em /> I believe it's gravity.
