Answer:
The scientific questions here are:
<em>a) How will climate change affect forests</em>
<em>b) How did life on Earth begin</em>
<em>c) Why did dinosaurs go extinct</em>
Explanation:
Scientific question are logical quantifiable questions, whose answers can be measured. A good scientific question must have answers that can be tested by a carefully designed experiment or measurement. Some qualities like "prettiest" and "amazing" cannot be tested for nor are they measurable, and hence, they do not make a testable component of good scientific question.
Maybe this will help you out:
Momentum is calculate by the formula:

Where:
P = momentum
m = mass
v = velocity
The SI unit:

So the unit of momentum would be:

Impulse is defined as the change in momentum or how much force changes momentum. It can be calculate with the formula:
I = FΔt
where:
I = impulse
F = Force
Δt = change in time
The SI unit:
F = Newtons (N) or 
t = Seconds (s)
So the unit of impulse would be derived this way:
I = FΔt
I =
x 
or

You can then cancel out one s each from the numerator and denominator and you'll be left with:

So then:
Momentum: Impulse

Answer:
A. Is the one that the experimenter manipulates directly
Explanation:
The independent variable is the one that is manipulated during an experiment by the experimenter.
The dependent variable is the one that is effected by the independent variable in an experiment.