Communication (from Latin commūnicāre, meaning "to share") is the act of conveying intended meanings from one entity or group to another through the use of mutually understood signs and semiotic rules.
Water is essential to life, but every year millions of the chemicals produced together with their reactants and by-products enter the water cycle. Many of these chemicals currently remain unidentified, and the risk posed to human health and the environment cannot be fully determined.
EN 
CS
DE
ES
FR
HU
IT
PL
PT
РУ
SK
TR
УК
AR
中文
