In Canadian football, while only 12* players are playing on the field at once, teams need more than just 12* players. They must have an offensive and defensive team. Most highâ¦ school football teams have 1st, 2nd, and 3rd string players, so thirty to forty players is a reasonable number.
Gastroenteritis may result from ingesting chemical toxins (see Chemical Food Poisoning). These toxins are usually produced by a plant, such as poisonous mushrooms, or by certain kinds of exotic seafood and thus are not the product of an infection.
The formation of a gas is another sign of a chemical change that can be seen or heard. Visually, gas formation can be seen when bubbles form in a liquid after two or more substances are mixed together. For example, if vinegar is added to baking soda, the mixture bubbles furiously as a chemical reaction occurs.