Why do you think this occurs?

Out of this list which can be classified as a chemical. Temperature sleep salt heat cold? If you work on a farm that is quickly losing its topsoil to erosion how can this be stopped? How is would formed? What does the wiring harness diagram for a 1970 corvette stingray convertible look like? What were the responses to hurricane Katrina? What does it mean when you hear a bang go through your body. Similar to feeling the bang when a old fashioned cannon goes off nearby.? Is Jupiter heavy or light? How much charge does 12.5x1018 electrons have? What are the four elements plants need to grow? A chemical agent that aids the body in its production of testosterone? Do all heterozygous pairs of allele produce an intermediate phenotype? What was John Needham's Experiment? What stops red cells escaping from a cut? Where are Schefflera plants mostly found? An important defense against diseases in vertebrate animals is the ability to eliminate inactivate or destroy foreign substances and organisms explain how the immune system achieves the following? What are two important facts to remember about earth's rotation? What is correct snow were falling or snow was falling? What are things passed on from earlier generations? What island is latitude 07S and 107E? What is the average temperature in the western region?

Why do you think this occurs?