Answer:
I think its sharply focused ultrasound but I'm not sure
Explanation:
A fish finder utilizes high frequencies of sharply focused ultrasound, which is transmitted with high voltage in order to determine the direction fish schools are moving. Locating objects in the air is different than locating objects in the water. I hope this helped ♡.
Answer:

Explanation:
Skin covers all the body surfaces. The purpose of the skin is protect the body against infection, injury, heat or cold and also to store water and vitamins.
Body surface area is measure of surface area of the human body. It is measured in
.
<u>There are many ways to measure the skin surface area of the body but the formula which is widely used is Mosteller formula, which is:</u>

That is true, you limit on what you can do with them.
I think it is keystone. If they were not there the population of urchins would go up and the kelp would go down.