Is mars Held in orbit by the gravitational pull of a planet

How many trophic levels are there in the following food chain? phytoplankton - shrimp - perch - pike - osprey

1. which of the following is correct regarding opiates/opioids: a. they all have a natural component as a starting pointb. they have low addiction possibilitiesc. methadone binds to some of the same receptorsd. a and care correcte. all are correct

Building glycogen from glucose molecules is an example of what