Which of the following is most likely to be studied by direct observation?
a) the motion of the stars and planets in the universe.
b) the growth of crops in response to certain fertilizers.
c) global wind patterns.
d) the spreading of the ocean floor

B) The growth of crops in response to certain fertilizers.

The inducible isoform (NOS-2) is calcium-independent and produces large amounts of gas that can be cytotoxic. NOS oxidizes the guanidine group of L-arginine in a process that consumes five electrons and results in the formation of NO with stoichiometric formation of L-citrulline.