In an expirement a scientist should

I suppose there are answer choices you forgot to list but in general

They should think of a question
They should form a hypothesis
Do research and test
Have an independent and dependent variable
Have repetitions and replications

If there’s answer choices put them in the comments and I’ll answer it

In reversible reaction chemistry equilibrium is attained when the forward and reverse reactions are taking place at the same rate, thus, the concentrations of reactants and products remain the same. a reversible reaction is a chemical reaction where the reactants form products that, in turn, react together to give the reactants back. in irreversible reactions on the other hand, the reactants react to form the products, which cannot revert back into reactants.