The ____________________ process fixes nitrogen from the air by attaching hydrogen atoms from ...

The ____________________ process fixes nitrogen from the air by attaching hydrogen atoms from
  natural gas to it. This reaction, in the presence of heat, pressure, and an iron catalyst, produces
  ammonia and is represented as 3H2 + N2  2NH3.

____________________ carriers include bone meal and manure, superphosphates, ammonium
  phosphates, and rock phosphate.

____________________ are common, useful, water-soluble trace element fertilizers, generally used in
  fluid form.

____________________ are a dry fertilizer with large, evenly-sized grains; spread evenly and easily
  with much less dust (fines still cause problems); and they are coated to reduce moisture absorption.