Please help! Fast, much appreciated

Which system revise and send electrical signals throughout the body

1. environmental factors, such as ph and temperature, can affect the function of an enzyme. a. true b. false 2. which of the following is an organic molecules (ex. vitamins) that an enzyme? a. coenzyme b. product c. active site d. substrate 3. how do enzymes effect the speed of a chemical reaction? a. they speed it up b. they slow it down c. they have no effect on the speed of a reaction 4. during a chemical reaction, an enzyme is used up so that it can only be used one time. a. true b. false 5. which of the following results from a chemical reaction that is catalyzed by an enzymes? a. active site b. product c. substrate d. coenzyme

When does the circulatory system work with the respiratory system? a. during blood cell formation b. during cellular respiration c. during intestinal digestion d. during a viral infection