Lead released into the environment makes its way into the air, soils, and water and can remain in the environment as dust, indefinitely. The EPA and the Centers for Disease Control and Prevention (CDC) agree that there is no known safe level of lead in a child's blood. Lead is harmful to health of all age groups, but especially children. The U. S. has banned leaded gas and leaded paints, yet this toxin is still found in our drinking water. What is the MAIN cause of lead inner drinking water?

How can scientists test their ideas about the origin of the universe if they can't physically interact with or study?

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

What happens when the cell copies its chromosomes