Which image exclusively represents the principle of radiation ?

usa testprep

The chemical reactions lab we did is typically called a "copper plating lab,  because the acid solution cleaned the pennies and made the copper look shinier;   the acid solution cleaned the paperclips and made them look like pennies;   &   the copper from the pennies was removed, and then added to the paperclips. 

A,d, and e on edgunuity

Repeated trials allow you to calculate a mean which can reduce the effect of random errors to make your results more precise.your results will also be reproducible therefore if someone else did the same experiment they'd get the same results which would make your results more reliable.