Pyrolysis oil are affected by temperature, reaction time, algae species, algae concentration, reaction atmosphere, and catalysts, in subcritical water reaction conditions. Bio-oil typically requires significant additional treatment to render it suitable as a refinery feedstock to replace crude oil derived from petroleum, coal-oil, or coal-tar. Tar is a black mixture of hydrocarbons and free carbon obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. Wood-tar creosote is a colourless to yellowish greasy liquid with a smoky odor, produces a sooty flame when burned, and has a burned taste. It is
English words of Greek origin words like "metabolize", though composed of a Greek root and a Greek suffix, are modern compounds. Greek and English share many Indo-European cognates. In some cases, the cognates can be confused with borrowings. For example, the English "mouse" is cognate with Greek μῦς /mys/ and Latin "mūs", all from an Indo-European word "*mūs"; they are not borrowings. Similarly, "acre" is cognate to Latin "ager" and Greek αγρός, but not a borrowing; on the other hand, the prefix "agro-" is a borrowing from Greek, and the prefix "agri-" a borrowing from Latin. Many are used verbatim in English texts—"et cetera" ("etc."),