Atmospheric nitrogen gas is not normally "available" to organisms. It's "fixed" or made available by:

Question

A. by the intense energy of lightening strikes

B. by nitrogen-fixing bacteria

C. by soybeans and other legumes

D. both a and b

E. all of the above

Answer 1

Open your science textbook!  You don't always get accurate answers here.

Lightning fixes a tiny amount of N, bacteria fixes most of the biologically fixed N.  Although legumes are often called "nitrogen fixing plants" they do not fix nitrogen but they engage in a symbiotic relationship with bacteria.  The bacteria fix nitrogen.

Answer 2

I think it's E, but I'm not 100%. I know that A and B are correct, and C is correct to a point; it is the bacteria in the plants that fix the nitrogen.