Average revenue can be represented in a table or as a curve. For a perfectly competitive firm, the average revenue curve is a horizontal, or perfectly elastic, line. For a monopoly, oligopoly, or monopolistically competitive firm, the average revenue curve is negatively sloped.
Carbon is the main constituent of all living cells. It has chemical properties that make it the most important biological element. For instance, it forms strong chemical bonds and can form single bonds with up to four other atoms. It can bond to itself. It can also form double and triple bonds. Carbon is one of the only elements, because of its bonding properties, that can create long chain-shaped molecules or ring shaped molecules.
The second of the big three elements in row two is nitrogen (N). Nitrogen is the seventh element of the periodic table. It is located between carbon (C) and oxygen (O). Along with carbon and oxygen, nitrogen is essential in most of the compounds that allow life to exist. It would be great if you remember that nitrogen is an important part of amino acids. We'll tell you again later, but you should always know that almost eighty percent of Earth's atmosphere is made of nitrogen gas.