3. Evaluate the validity of the following statement and explain your reasoning. Once scientists believe something to be true, they will say so with 100%
certainty.

If the scientist makes a statement so it is 100 % valid.

Explanation:

Once scientists believe something to be true, they will say so with 100%  certainty. This statement is true because the statements of the scientist is not based on theories. Scientist make any statement after performing many experiments in order to verify the statement. So if the scientist will say about something with 100 percent certainty so it is considered as valid because the statement goes through from a number of experiments.

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme

b is the best answer for this question.