Any metabolic waste product that contains nitrogen. Urea and uric acid are the most common nitrogenous waste products in terrestrial animals; freshwater fish excrete ammonia and marine fish excrete both urea and trimethylamine oxide.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。