Rational numbers: {p/q | p and q are integers, and q =0}: Real numbers: {x | x is a number that can be written as a decimal}. Irrational numbers: {x | x is a real number andx cannot be written as a quotient of integers.}. Deï¬nitions: â¢ The number of elements in a set is called the cardinal number,orcardinality,oftheset. The symbol n(A), which is read ân of A,â represents the cardinal number of the setA.
The Intergovernmental Panel on Climate Change (IPCC) reported in 2014 that scientists were more than 95% certain that global warming is mostly being caused by human (anthropogenic) activities, mainly increasing concentrations of greenhouse gases such as methane and carbon dioxide (CO2).
The term global warming refers to the increasing average temperature of the Earth. This increase may be due to many processes, but the principal cause is the increasing levels of greenhouse gases, mainly carbon dioxide.