How do you breath in freefall?"
-- Through genetically developed gills.
This falls into the realm of urban folklore. One CAN breathe in freefall - if it were necessary. However, due to the high speed of terminal freefall (and much higher speeds in vertical freefall dives), the jumper's body is exposed to O2 molecules at a much higher rate than someone walking around on the ground. The body is able to absorb the necessary O2 through the skin. This is why jumpers flap their cheeks in freefall, it presents a larger surface area to the airstream for oxygen osmosis. Once under canopy, the jumper resumes breathing normally.
This is also why jumpers do not jump on cloudy days or when they might risk going through clouds. The moisture in the clouds can condense on their exposed skin surfaces preventing the absorption of the necessary oxygen resulting in suffocation. AADs are recommended for jumpers in climates where weather is a factor.
"Don't your ears pop on the way down?"
-- "Yes, we're not ignoring you, we're deaf." "What if you have to go the bathroom in the plane?"
-- "Go ahead!" "Can you steer your parachute?"
-- "No, one time I landed in Jamacia." "Does it hurt?"
-- "Yes, that's why we jump all the time! Masochism!" "What if your parachute doesn't open?"
-- "Gee, I never thought of that..." "Why do you jump?"
-- "Why do _you_ breathe?" "Where do you jump?"
-- "O'Hare, Midway, LAX, Dulles, where ever I happen to be." (:-)