I am a single-celled organism that lives nearly everywhere. I often form the basis of food chains, providing nutrients for other organisms. What am I?​

If you were running a marathon, which type of muscle fibers would be most useful to you? a. slow-twitch b. fast-twitch, type i a c. intermediate-twitch, type ii b d. slow-intermediate twitch, type i b select the best answer from the choices provided. a b c d