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.
Environmental chemists study the toxicity of various chemicals, that is, how those chemicals affect plants, animals, and people. Environmental scientists in research positions with the Federal Government or in colleges and universities often have to find funding for their work by writing grant proposals.