How big is a blood cell? how does its size compare to dust mites, and then to the e. coli bacteria?

When a scientific theory has been tested and proved by the scientific community, it becomes a law

How does a catalyst increase the speed of a reaction? a. the catalyst eliminates the activated complex stage, allowing products to form immediately. b. the catalyst lowers the energy level of the reactants, making it easier for them to react. c. the catalyst makes it easier for the activated complex to form, lowering the activation energy. d. the catalyst raises the energy level of the products, making the reaction finish sooner. reset next

Which number should be placed before f2 on the reactants side equation to make equation balanced? xe + > xef4