Metal ores are often formed near rocks associated with: volcanic eruptions dead organisms Human impacts

gas

explanation:

smoke is the matter of a gas

a is the correct answer

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.