What instrument us normally used to measure atmospheric pressure

Can someone me with questions 12 and 13 plz.

This image is an example of a(n) a) atom. b) compound. c) mixture. d) molecule.

What method(s) do plants use to obtain nitrogen? select all that apply. absorb it from the atmosphere use bacteria to convert nitrogen to usable form obtain usable nitrogen compounds from the soil absorb nitrogen from water taken in at the roots