What is a function of smooth endoplasmic reticulum?

What type of organism is a one-celled organism that functions as a single unit? a. bi-celled b. single-celled c. pre-celled d. multi-celled

Which gas found in the earth's atmosphere greatly impacts the daily range of temperature on earth. a) oxygen b) hydrogen c) nitrogen d) water vapor

Coral have a symbiotic relationship with what in order to eat?