Answer:
D
Explanation:
What can be infer from Mr. F situation is that his body is raising blood pressure by both increasing blood volume with all this fluid intake and increasing heart rate. Something may be wrong with his blood volume.
If both waves have the same wavelength, then the amplitude of
their sum could be anything between 1 cm and 9 cm, depending
on the phase angle between them.
If the waves have different wavelengths, then the resultant is a beat
with an amplitude of 9 cm.