Which of the following events could increase Earth's temperature? Question 2 options:

A. a decrease in the relative percent of greenhouse gases

B. planting more trees

C. widespread removal of tropical forests

D. a reduction in the use of fossil fuels

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 ?