gas exchange / chemical makeup / natural and human managed systems / shared writing products / organ systems / biotechnology / reproductive technology techniques / animal agribusiness / energy flow / programs involving biotechnology / cell systems / chemical process / reproductive and genetic technologies / inter-organizational systems / multi-cellular systems / endocrine and nervous systems / organs systems / vertebrate animal organ systems / instructional tool / Compare energy availability / biological and chemical levels / animal cells exchange/convert energy / circulatory and respiratory systems / biotechnology applications / chemical bonds / energy / /