Questions

Crossover rates have to do with the amount of earnings that are generated by two different but similar projects. The crossover rate is the point at which the two projects achieve the same net present value. In terms of investments, calculating a crossover rate between two similar securities can help an investor determine what to buy and what to sell.

Arunachal Pradesh State has been declared as the Open Defecation Free state.

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.