Final answer:
The amplitude of one wave is affected by the amplitude of another wave only when they are precisely aligned. This is known as constructive interference.
Step-by-step explanation:
The statement is a. True. The amplitude of one wave is affected by the amplitude of another wave only when they are precisely aligned. This is known as constructive interference. When two waves of the same amplitude and frequency are in phase, meaning their crests and troughs align, they will combine to create a wave with a larger amplitude. On the other hand, if the waves are out of phase, meaning their crests and troughs do not align, they will interfere destructively, and the resulting wave will have a smaller amplitude.