Answer:
hydrogen
Explanation:
The gas with the least molecular weight effuses the fastest (Graham's Law). Hence, H gas has a higher rate of diffusion compared to N, O, and Cl.
So, Cl is the slowest when it comes to the rate of diffusion, because it has the highest molecular weight.
<span>bright yellow light and lots of heat-energy.</span>
Scientists should control most possible variables in experiments to get the most valid and correct data. If many variables are included in experiments it is more difficult to interpret what is causing a different outcome.
I think it would be penicillin as it saved many lives in its time and ours.