A fact is a pragmatic truth, a statement that can, at least in theory, be checked and confirmed. Facts are often contrasted with opinions and beliefs, statements which are held to be true, but are not amenable to pragmatic confirmation.The word fact derives from the Latin Factum, and was first used in English with the same meaning: "a thing done or performed", a use that is now obsolete. The common usage of, "something that has really occurred or is the case", dates from the middle of the sixteenth century. Fact is sometimes used as synonymous with truth or reality, as distinguishable from conclusions or opinions. This use is found in such phrases Matter of fact, and "... not history, nor fact, but imagination."
A jet stream is a narrow variable band of very strong predominantly westerly air currents encircling the globe several miles above the earth.
Es completamente verdadero, está en el mapa
UV radiation generates ground-level ozone (O3) and some particulate matter (PM, frequently called aerosol) that include nitrate, sulfate, and organic aerosols causing adverse effect on human health and the environment. UV promotes the formation of hydroxyl radicals that act as cleaning agents for troposphere
Radiation has been around us throughout our evolution. So our bodies are designed to deal with the low levels we're exposed to every day. But too much radiation can damage tissues by changing cell structure and damaging DNA. This can cause serious health problems, including cancer
