During human digestion, the bolus enters the stomach through the esophagus via the lower esophageal sphincter. the stomach releases proteases and hydrochloric acid, which kills or inhibits bacteria and provides the acidic ph of 2 for the proteases to work. food is churned by the stomach through muscular contractions of the wall called peristalsis and the bolus is converted into chyme. according to the text, the stomach's environment is very acidic. how does this acid stay in the stomach?

Which phrase is the best summary of the model shown? a. the transfer of the sun's energy through trophic levels b. a series of aerobic and anaerobic reactions c. a transformation of light energy into chemical energy d. the breakdown of food molecules

(select all the correct choose each statement that is scientific. - the opinions of randomly selected participants in a survey prove the idea that global temperatures are not increasing on earth. - the universe's average temperature and rate of expansion support the idea that it began as one super-dense and hot mass 13.8 billion years ago. - ocean tides are caused by the uneven gravitational pulls of the moon and sun on different parts of earth. - human life is more valuable than other forms of life on earth because humans are more intelligent than other organisms.

Tropical rain forests support more species per unit area than any other terrestrial ecosystem. what is one way rain forests are important to the health of the biosphere?