Introduction Chewing gum in various forms has been around since ancient times. The Greeks chewed sap from the mastic tree, called mastiche. On the other side of the world, the ancient Mayans favored the sap of the sapodilla tree (called tsiclte).
Bioremediation is a waste management technique that involves the use of organisms to remove or neutralize pollutants from a contaminated site.ioremediation may occur on its own (natural attenuation or intrinsic bioremediation) or may only effectively occur through the addition of fertilizers, oxygen, etc., that help encourage the growth of the pollution-eating microbes within the medium (biostimulation).
Active and passive transport processes are two ways molecules and other materials move in and out of cells and cross intracellular membranes. Active transport is the movement of molecules or ions against a concentration gradient (from an area of lower to higher concentration), which does not ordinarily occur, so enzymes and energy are required. Passive transport is the movement of molecules or ions from an area of higher to lower concentration. There are multiple forms of passive transport: simple diffusion, facilitated diffusion, filtration, and osmosis. Passive transport occurs because of the entropy of the system, so additional energy isn't required for it to occur. Compare. Both active and passive transport move materials and can cross biological membranes. Contrast