Answer the question based on the following text.  Question:   We are designing a submarine to study fish that live far below the surface of the ocean. Before we can send a human researcher down in the submarine, we have to be sure it can tolerate the pressure of the water without cracking. The tougher test will be to send our submarine down to 500 feet or or 1500 feet??    Text:  A fluid exerts pressure in all directions, but the pressure is greater at greater depth.
The answer to this question is:
1500 feet?