In biology, cell theory is a scientific theory which describes the properties of cells. These cells are the basic unit of structure in all organisms and also the basic unit of reproduction.
The doctype declaration should be the very first thing in an HTML document, before the <html> tag. The doctype declaration is not an HTML tag; it is an instruction to the web browser about what version of the markup language the page is written in. The doctype declaration refers to a Document Type Definition (DTD).
OpenType is a format for scalable computer fonts. It was built on its predecessor TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior.penType features are tedious to define using a GUI. Consequently, Adobe standardized a text specification format for feature files, which typically have a name ending in a .fea extension. These files can be compiled into the binary font container (.ttf or .otf) using Adobe FDK (AFDKO), FontLab or FontForge.