<span>Tri- in phosphate meand three. Tri- is formed from the Latin word "tres" and Greek word "treis".It is usually used in the beginning of nouns and adjectives that have three as part of their meaning.In chemistry, it means having three atoms, groups or equivalents.</span>
I think the best medium is agar. It is a jelly-like substance that is obtained from algae, and is used to culture small organisms such as microorganisms and bacteria.
Hope this helps. :)
