Trace gas Trace gas The most abundant gases in the atmosphere are nitrogen (78.1%), oxygen (20.9%), and argon (0.934%). Combined, oxygen, argon, and nitrogen make up 99.934% of the gases in the atmosphere (not including water vapor). The other gases that are not part of the 99.934% of the atmosphere are called trace gases. The abundance of a trace gas can range from a few parts per trillion (ppt) by volume to several hundred parts per million by volume (ppmv). When a trace gas is added into the atmosphere, that process is called a "source". There are two possible types of sources
Most common words in Spanish (CREA), a text corpus compiled by the Real Academia Española (RAE). The RAE is Spain's official institution for documenting, planning, and standardising the Spanish language. A "word form" is any of the grammatical variations of a word. The second table is a list of 100 most common lemmas found in a text corpus compiled by Mark Davies and other language researchers at Brigham Young University in the United States. A "lemma" is the primary form of a word—the one that would appear in a dictionary. The Spanish infinitive "tener" ("to have") is a lemma, while "tiene" ("has")—which is a conjugation