This document defines key vocabulary terms related to ecological cycles. It describes processes like ammonification, where bacteria break down amino acids into ammonium; cellular respiration, where organisms create energy from glucose; decomposition, the breakdown of matter by bacteria and fungi; nitrification, where nitrifying bacteria convert ammonia to nitrites and nitrates; nitrogen fixation, where nitrogen gets "fixed" and combines with oxygen or hydrogen; photosynthesis, where plants make sugar from carbon dioxide and water; precipitation, when water droplets in clouds become too heavy and fall; respiration and decay, where animal life and bacteria consume oxygen and release carbon dioxide; transpiration, where plants lose water through their leaves; and weathering, the physical and chemical breakdown of