Ecology overview - review of lessons 1 - 7 quiz- multiple choice- === 1. which of the following are biotic factors and which are abiotic factors? (1 point) b. algae and fungi are biotic; temperature and rainfall are abiotic. === 2. why is it useful for an ecologist to identify the keystone species in an ecosystem? (1 point) c. the keystone species is critical to maintaining the stability of an ecosystem, and changes in its population indicate changes in ecosystem health. === 3. competition over resources occurs between organisms. c. attempting to occupy the same niche. === 4. the lowest trophic level in an ecosystem. b. has the greatest biomass === 5. what is true of the energy that is passed from one trophic level to the next in a food chain? b. about 10% of the stored energy of one level becomes stored energy at the next higher level. === 6. autotr