What is depth perseption?

Does the Great Escarpment have highlands that drop sharply into the Atlantic Ocean? What treaty allowed Americans free navigation of the Mississippi River and the right to use the port at new Orleans duty free? Do you have to leave your family to go to Everest? What injections do you need for Egypt? Are bats mostly found in the tropical rain forest? What the great pyramid of Giza symbolizes? Where most salt in ocean water come? What surrounded the missions? Why is the ocean the earth's thermostat? How does the Sahara desert help people? How many clown fish live in the oceans? How deep does underground drainage have to be buried? How did the Colosseum get its name? What is that structure under the peace bridge? What color is Mount Everest? How coral reef protect us from strong storm? What kind of land does blue ridge have? When will the new Panama Canal open? What is the entrance fee for Banff national park? How do beaches help the environment?