Unit four. wonder. wonder . does . IT does IT . measured. measured . square . kilometer. square kilometer. below. below . level, level c . level, sea level. surface. surface . depth. depth. dive. dive. submersible. submaster ble. unusual. unusual. Bottom m bottom waters. watership . civilization. civilization. at all costs. at all . costs, development. development, cubic, cubic. cubic meter. cubic meter. mile. mile. pool . pull. climate. climate. northern. northern. distance. distance. survive. survive. condition. condition. degree. degree. Cliff. Cliff. changeable. change. table. death, death. determined. determined. above. above. Teammate. teammate. shoulder. shoulder. bit by bit. bit . by . bit . der. measure. measure, successfully, successfully. Risk. risk. curiosity. curiosity. ambition, ambition. explorer. simply. simply. risky. risky. Southern. southern. located . in . fresh . water. fresh . water. type type. attract. attract. curious. curious. traveler. traveler. natural. natural . reef. reef. underwater. underwater. northeastern. northeastern . coast. coast. coral . correll . include. include . sand. sand. alive. alive. structure. structure. turtle. turtle. lifetime. lifetime. Nile . river, nile river. Angel falls. Angel falls. mount, try along . a mount, try along . a dead sea. sahara . does IT. sahara . desert, mariana . trench. marianna . trench. stanic, titanic. Young sea. river, yang, sea river. egypt. egypt. telia . can desert tech . market . does IT, mount kilda. mount killer jo. inger falls. anger . falls, east . african rift valley. east african rift valley. Victoria falls. Victoria . falls George . mallory. George . mallory. siberia. siberia. Blake by cow lake, bike cow, belgium, great . barrier ef. great barrier reef.