One of the following questions will appear at the top of your copy of the Final Exam.  If you answer the question correctly you will then have the right to refuse to answer one of the remaining numbered questions on the exam.  Simply write "Refuse" next to the question of your choice and you will be given full credit for that question.  Choose wisely.  Every answer on the exam is worth one point.  Thus it makes more sense to refuse to answer a multiple part question that you are not sure of than a single part question.

1.     Photosynthesis is the source of most of the _________________________ in the air.

2.     What is the name given to lightning that comes from thunderstorms that are producing rain that evaporates before reaching the ground.

3.     Photodissociation of oxygen by ultraviolet light is the first step in the production of _________________________.

4.     The blue color of the sky is caused by
        a. absorption of UV light by ozone          b. scattering of sunlight by air molecules
        b. reflection of sunlight by the ocean       d. plants and photosynthesis

5.     What is St. Elmo's fire