Atmosphere
Barometer.
intriguing
Another name for air resistance is aerodynamic drag.
Their is not another name for HIV that starts with an R. That said, HIV is a type of retrovirus. That is probably the word you are looking for.
Another name of a dog house is a kennel.
Rubella is another name for German measles.
Another name for a hot air balloon is an aerostat.
aqueduct
Tarsus
longitude
a questionnaire? :)
soil