3points
when you and your friend have different standards, you might have a conflict
over what difference between you?
a. assumptions
o
o
b. knowledge
o
o
c. values
d. expectations

the answer is expectations.. synonym for standard

out of the choices i'd say d the ability to set goals, mainly because to desire to continue you need motivation but it isn't motivation in that part, but setting goals means you have an endgame and you want to reach it which sums up motivation.

answer(b) keep oxygenated and deoxygenated blood separate;