The inert gas which is substituted for nitrogen in the air used by deep sea divers for breathing, is a. argon b. xenon c. helium d. krypton the gases used in different types of welding would include a. oxygen and hydrogen b. oxygen, hydrogen, acetylene and nitrogen c. oxygen, acetylene and argon d. oxygen and acetylene the property of a substance to absorb moisture from the air on exposure is called a. osmosis b. deliquescence c. efflorescence d. desiccation in which of the following activities silicon carbide is used? a. making cement and glass b. disinfecting water of ponds c. cutting very hard substances d. making casts for statues the average salinity of sea water is a. 3% b. 3.5% c. 2.5% d. 2%