Chemical element element (by mass) making up Earth, while oxygen is the most common element in the Earth's crust. Chemical elements constitute all of the ordinary matter of the universe. However astronomical observations suggest that ordinary observable matter makes up only about 15% of the matter in the universe: the remainder is dark matter; the composition of this is unknown, but it is not composed of chemical elements. The two lightest elements, hydrogen and helium, were mostly formed in the Big Bang and are the most common elements in the universe. The next three elements (lithium, beryllium and boron) were formed mostly
Meta element While clicks for a result can be a positive sign of effective codice_29 and codice_25 writing, Google does not recognize this meta element as a ranking factor, so using target keyword phrases in that element will not help a site rank better. W3C doesn't specify the size of this description meta tag, but almost all search engines recommend it to be shorter than 155 characters of plain text. The codice_31 attribute tells search engines what natural language the website is written in (e.g. English, Spanish or French), as opposed to the coding language (e.g. HTML). It is normally an IETF