Variables is likely the correct answer.
In the question in regard to the ouchterlony test if there is an unknown antigen containing a swine serum album, the number of precipitin line that will form is one which is the answer. It relies in between the wells of the antibodies for the bovine albumin and the wells of the bovine albumin.
What defines a plant is if it alive, and leaves or contains pollen or seeds I hope this helps and is correct
