Because the door is heavy.
A is the answer because the cause for doing well on the test is that she studied and the effect is that she did well. Hope that helped
Answer:
hums? or is this asking if these are an infrasound than no
Explanation:
because the sound has to extend below the range of human hearing (from 20 Hz down to 0.001 Hz)
Most likely it means something relating to birds.
