15 POINTS The independent variable is the only factor that a scientist:

Options:
varies for different groups in an experiment.
measures in an experiment.
keeps constant for each group in an experiment.
records throughout an experiment.

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?