Answer:

Explanation:
Given that,
The position of a particle is given by :

Let us assume we need to find its velocity.
We know that,

So, the velocity of the particle is
.
the answer in my opinion would be A
Answer:
True
Explanation:
An independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable. You are changing light or dark
Answer: I am pretty sure that you should pick radio waves.
Explanation: The scientist should use radio waves. I think this because you can use the radio waves to analyze the signals from outer space. This will work much better than anything there, to analyze it the best possible.
The best I could do.