Answer: TWO.
At least two groups: treatment group and control group.
The treatment group is that is exposed to the different levels of the independent variable ( a medication for example), while the control group is not treated, so the researchers can compare the effect of the medication.
Black hole, or a singularity contained within an event horizon through which no light can escape.
Answer:
Because it went through a chemical change which changes its atomic form
Easy peasy! All we need to do is plug this formula into our calculator:
-log(M)
So, we'd plug in -log(.2), which is 0.7 :)
Answer:
it can cause irritation in eyes throat and lungs and u can become lightheaded, or possibly fall in a coma