What is the most important determinant of the timing of the onset of pubescence?

A nuclear reactor simulator used in training is said to have good physical fidelity. This means that:

A) trainees are required to demonstrate a high level of physical skill in the simulator. B) the simulator was inexpensive to construct. C) the simulator mimics a real nuclear reactor. D) there are no physical hazards associated with training in the simulator.

Without heroin, withdrawal symptoms begin to appear in:

A) 2 to 4 hours. B) 6 to 8 hours. C) 10 to 12 hours. D) 14 to 16 hours.