What is the role of a control group in any experiment

A control group is what is monitored and maintained throughout the experiment. This gives the experimenters a baseline to go off of and compare the experimental group's data to.

the correct answer in apex is tissue development, i know because i just had this question

in a chemical reaction, the atoms and molecules produced by the reaction are called products. no new atoms are created, and no atoms are destroyed. in a chemical reaction, reactants contact each other, bonds between atoms in the reactants are broken, and atoms rearrange and form new bonds to make the products.