It can be, but set also means many other things.
The flow of Direct current (DC) is constant and flows in one direction. Most digital electronics make use of DC. Alternating current (AC) periodically flows in reverse and is mostly used to deliver power to houses, buildings and the like. With that alone, you can already rule out A, C and D.
The answer would then be B. constant, periodically reversing.
<span>The Gravitational Force of an object is a measure of the amount of matter it contains. on the other hand __Matter__ is a measure of the gravitational force on an object. I hope it helps :)</span>
Answer:
Your answer is D It does not need to be repeatable.
the reason for this is because C is correct.
You need to be able to experiment on something multiple times so that you can gather further data to imbedded your evidence in facts.