第10週作業ch3-6翻譯

ch3-6：What happens to matter in an ecosystem?(生態系中的物質發生什麼事?)
p57~Nitrogen Cycles through the Biosphere：Bacteria in Action的第一段：
Nitrogen is the atmosphere's most abundant element. The major reservoir for nitrogen is the atmosphere. Chemically unreactive nitrogen gas(N2) makes up 78% of the volume of theatmosphere. Nitrogen is a crcial component of proteins, many vitamins, and nucleic acids such as DNA. However, N2 cannot be absorbed and used directly as a nutrient by multicellular plants or animals.
氮是大氣中最豐富的元素，主要儲存於大氣中，占大氣的78%。雖然氮氣是組成蛋白質、維他命、核酸的關鍵成分，但卻不易直接被吸收利用。