Which of these represents a synthesis reaction?

a. agno3 + hcl -> agcl + hno3
b. zn + 2hcl -> zncl2 + h2
c. n2 + 3h2 -> 2nh3
d. 2kclo3 -> 2kcl + 3o2

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