Which statement about tobacco use is true
a. smokeless tobacco can lead to cancer but is not addictive
b. smoking relaxes people because it lowers the heart rate
c. smoking. an lead to emphysema as well as strokes

You are travelling on a long non-stop flight from tahiti to tampa. you have been in the air for about 7 hours and have not moved, since you boarded the plane at tahiti. you need to use the rest room and on standing up feel dizzy. the best explanation for your dizziness