Exposed rocks are mechanical since it is exposed to the outside elements a.k.a the weather and it's wearing down it's composition naturally,it would be chemical if you dropped into a solution or something to alter the rocks composition...hope this helps.
They help ensure that the changes of the independent variable are affecting the dependent variable
<span>8. Chitinase is an enzyme that breaks down the chitin molecules in an insect's exoskeleton. The sequence of amino acids in the chitinase is an example of which level of protein structure?
==> primary
9. The amount of energy needed for a reaction to take place is the activation energy. Enzymes can lower the activation energy of a chemical reaction. Which of the following describes a way that this could happen?
==> Molecules can be brought together so they will bond more easily.
10. What is one way that RNA differs from DNA?
==> It is single-stranded.
11. Which molecule do mammals use to store extra glucose in their muscles?
==> glycogen
12. Which molecule do plants use to store extra glucose?
==> starch
13. Which element is present in all amino acids, but not necessarily in fats or carbohydrates?
==> nitrogen
14. Which statement best describes the role of DNA in the body?
==> It contains genetic information.
15. Which statement best explains how enzymes speed up chemical reactions?
==> Enzymes lower the activation energy of a reaction.</span><span>
</span>
