Which of the following correctly described a compound

Read these sentences from the text. near the equator, the tropics receive the most rain on a consistent basis. as a result, the fresh water falling into the ocean decrease the salinity of the surface water in that region. [. .] . . as the salt content of sea water increases, so does its density. what can you infer about how rain affects the density of surface water near the equator?

Can someone me with questions 15 to 17 plz.

At 450 mm hg a gas has a volume of 760 l, what is its volume at standard pressure