Help Me Please The human digestive system is approximately 900 cm long. Food is moved through the digestive tract. primarily by-
A- hydrochloric acid in the stomach
B- the enzymes amylase and pepsin
C-bile produced by the pancreas
D- muscular contractions​

D

Explanation:

the movement of your digestive system is through muscles within your wall that contract to push food down.

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 think the answer is gold im not entirely sure