The opposite of an acid is a base, and that's exactly what an antacid is. Antacids make you feel better by increasing the pH balance in your stomach. The pH system is a scale for measuring the acidity or alkalinity of a given environment (in this case, your stomach). The scale goes from 0 to 14. A pH of 7 is neutral. Below 7 is acid. Above 7 is alkaline.
Economy is the large set of inter-related economic production and consumption activities which aid in determining how scarce resources are allocated.
A market economy is an economic system in which individuals own most of the resources - land, labor, and capital - and control their use through voluntary decisions made in the marketplace. It is a system in which the government plays a small role. In this type of economy, two forces - self-interest and competition - play a very important role.