Why tryptophan has difficulty getting into your brain and making you sleepy on its own

All other things being equal the size of a population will decrease if

Based on the data in the graphs do you think pepsin and trypsin are found in the same part of the body? explain your answer.

Omar paddles a canoe downstream at a rate of 5 mi/hr. the stream is flowing at a rate of 12 mi/hr. what is the actual velocity of the canoe? a: 5 mi/hr, downstream b: 7 mi/hr, downstream c: 12 mi/hr, downstream d: 17 mi/hr, downstream