Pls

to be scientific useful, observations and experiments must be

a. inexpensive and deducible

b. repeatable and verifiable

c. morally justifiable and financially feasible

d. adaptable and abstract

The answer to this question would be repeatable and verifiable. If the result of the research can't be repeated then you can't deduce anything from it. The result should be verified so no one can falsify a claim of observation.

Morality and the inexpensive shouldn't be mandatory.

The antagonist is Marshall because he tripped Jeff and made Jeff late for the buss