Which of the following countries is responsible for releasing the largest amount of greenhouse gases?

The two gases making the highest relative contribution to the greenhouse effect are:

Study carefully the following pie diagram representing the relative contribution of various greenhouse gases to total global warming. Identify the gases $A, B, C$ and $D$.

Greenhouse gases are:

$El\; Nino$ effect is closely associated with

Which of the following gases contributes $14\%$ to the greenhouse effect?