When the nutrient concentration is higher in the lumen of the small intestine than in the absorptive cells, the difference in nutrient concentration drives the nutrient into the absorptive cells by

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.

answer; benefit; harmed;