Questions

A greenhouse gas is a gas in an atmosphere that absorbs and emits radiant energy within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. 

Carbon dioxide is a main greenhouse gas, found in car exhaust pipes.
Methane and nitrous oxide is another type of greenhouse gas.

Oxygen is the only clean gas out there because we need it to survive. Therefore, the only gas that is not a greenhouse gas is Oxygen.

Change control management is utilized from the begining to the end of the project in order to keep it focused with an emphasis on the time and budget. Answer A is incorrect because change control management is not seperate from the other phases. Answer B is incorrect because the control plan must be throughout the other phases of a project. Its usage is not optional, and consistent utilization is imperative to managing scope creep and other scope expansions. Answer C is incorrect because the project sponsors is generally not responsible for the change control documentation, although it should be involved in the buy-in and approval process.