A. The onset of the menstrual flow
Sperm production is hormonally driven. Brain hormones govern sperm production and are precisely controlled. So I say yes
In chemical reactions the substances present at the start of the reaction are reactant and the substances produced are called product
The kinetic molecular theory of matter states that: Matter is made up of particles that are constantly moving. All particles have energy, but the energy varies depending on the temperature the sample of matter is in. This in turn determines whether the substance exists in the solid, liquid, or gaseous state.