Limulus polyphemus are the source of calcitonin used to treat osteoporosis growth hormone used to treat dwarfism hydroxyapatite used to treat arthritis cells for the lal test used to detect bacterial contamination of surgical tools prialt, a peptide used as a pain reliever

Limulus polyphemus are the source of cells for the LAL  test used to detect bacterial contamination of surgical tools.

Limulus amebocyte lysate (LAL) is an aqueous extract of blood cells from the Limulus polyphemus which is used in LAL test. LAL test includes the reaction between LAL and bacterial endotoxin lipopolysaccharide (LPS), which is a membrane component of gram-negative bacteria. LAL test is widely used for the detection and quantification of bacterial endotoxins.

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)

i believe it would be c: tons.