Quadrilateral. In Euclidean plane geometry, a quadrilateral is a polygon with four sides (or 'edges') and four vertices or corners. Sometimes, the term quadrangle is used, by analogy with triangle, and sometimes tetragon for consistency with pentagon (5-sided), hexagon (6-sided) and so on.
Some environmental scientists and specialists focus on environmental regulations that are designed to protect peopleâs health, while others focus on regulations designed to minimize societyâs impact on the ecosystem.
Career: Environmental Scientists. Environmental scientists use their expertise to protect natural resources. If you're interested in chemistry, you might examine how certain chemicals affect plants, animals, and people. If you're interested in ecology, you might research the way rainfall, temperature, pollutants, and human activity affect an area.