| environ. |
carbon dioxide A colourless gas with a faint tingling smell and taste. Atmospheric carbon dioxide is the source of carbon for plants. As carbon dioxide is heavier than air and does not support combustion, it is used in fire extinguishers. It is a normal constituent of the atmosphere, relatively innocuous in itself but playing an important role in the greenhouse effect. It is produced during the combustion of fossil fuels when the carbon content of the fuels reacts with the oxygen during combustion. It is also produced when living organisms respire. It is essential for plant nutrition and in the ocean phytoplankton is capable of absorbing and releasing large quantities of the gas, CO2 (一种无色的气体，有淡淡的刺激性气味和味道。大气中的二氧化碳是植物的碳源。由于二氧化碳比空气重并且不支持燃烧，二氧化碳被用作灭火剂。它是大气的基本组成部分，相对无害，但是在温室效应中扮演着一个重要的角色。它是碳和氧气在燃烧过程中发生反应而产生的，也在生物体呼吸时产生。它是必要的植物营养，而且海洋浮游植物也能吸收和释放大量的二氧化碳。) |
