Q. Ships use _____ to find the depth of the ocean beneath them.
(A) pitches
(B) echoes
(C) frequencies
(D) none of these
The answer is: (B) echoes
Q. Ships use _____ to find the depth of the ocean beneath them.
(A) pitches
(B) echoes
(C) frequencies
(D) none of these
The answer is: (B) echoes