The box of rocks will have depression which can be seen without touching the box.
Explanation:
The density of rocks is very large as compared with napkins. So, the weight of the rocks will be much more greater than that of napkins.
As both boxes have same volume the heavier box will show depression on the lower surface as compared to the lighter box. So, the box of rocks will have depression which can be seen without touching the box.
Answer: Although low frequency sound travels further than high-frequency sound, calls at higher frequencies give the bats more detailed information--such as size, range, position, speed and direction of a prey's flight. Thus, these sounds are used more often.
