What two pieces of information are needed to determine ocean depth through echo sounding?

Sonar is an instrument which is used to search for things which are underwater. It is also used to find the depth of water by giving out ultrasonic vibrations into the water. The time which the vibrations take to return assists to find the distance of the reflecting surface.  

The correct answer is:

•velocity of the wave and  

•the return time of the wave.

Echo sound is the method for determination the water depth, based on transmitting sound waves into water. Two things that are recorded are the time interval between emission and return of a pulse and the speed of sound in water at the time.

answer: tributaries flow into rivers.

wetland is a biome that develops when the water gets accumulated in a land exhibiting a huge depression. these form either seasonally or permanently. the water in the wetland comes from rivers, lakes, ocean, flood, rain or other sources. the wetlands includes mangroves, marshes and peatland.

tributaries flow into the rivers develops a wetland because such water will get deposited in the depression and will restrict the original flow of tributary water. hence, water with low drainage current combines with the river water.

because of