a) It's caused by bacteria. Pericoronitis is an infection. It's caused by normal oral bacteria, like those found in dental plaque. It's the gum relationship around a partially-erupted tooth that allows pericoronitis to occur.
A futures exchange or futures market is a central financial exchange where people can trade standardized futures contracts; that is, a contract to buy specific quantities of a commodity or financial instrument at a specified price with delivery set at a specified time in the future. These types of contracts fall into the category of derivatives. The opposite of the futures market is the spots market, where trades will occur immediately (2 business days) after a transaction agreement has been made, rather than at a predetermined time in the future.
Currency futures contractsContracts that require the exchange of a specific amount of currency at a specific future date and at a specific exchange rate. are contracts that require the exchange of a specific amount of currency at a specific future date and at a specific exchange rate. The forward exchange rate is the exchange rate at which a buyer and seller agree to transact a currency at some date in the future. 2  Swaps, options, and futures are additional types of currency instruments used in the forward market.