Fact 1: Sonar is used to find the location of an object.

Fact 2: Periscopes are still useful, despite the sonar and electronic sensors of modern submarines.

Given the two facts above, answer the question "periscopes are used to find out what about objects" with the following options: 
- microscopic
 - density
 - location
 - weight
 - Light
 - energy
 - observe it
 - age


 

   location      