Answer:
The two measures required are:
C. The speed of sound waves.
D. The amount of time it takes sound waves to travel to the seafloor and back.
Step-by-step explanation:
To measure the distance between the seafloor and the ship, it's very important to know:
i. the speed of the waves
ii. the amount of time it takes the sound to travel and back.
When estimating water depth, the speed of sound through the water is used. Then the formula for the simple calculation is given as:
Distance = speed x time.
Where speed is the speed of the sound waves and time is the amount of time it takes the sound to travel and back.