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).
Most climate scientists agree the main cause of the current global warming trend is human expansion of the greenhouse effect 1 â warming that results when the atmosphere traps heat radiating from Earth toward space.Certain gases in the atmosphere block heat from escaping. blanket around the Earth. A layer of greenhouse gases â primarily water vapor, and including much smaller amounts of carbon dioxide, methane and nitrous oxide â acts as a thermal blanket for the Earth, absorbing heat and warming the surface to a life-supporting average of 59 degrees Fahrenheit (15 degrees Celsius).