Which statement is true?
A) Unicellular organisms cannot obtain energy or reproduce, but they can maintain structure (homeostasis).
B) Unicellular organisms don't have to do anything - they are only just one cell!
C) Unicellular organisms have to meet the 3 main challenges of life. They have to obtain energy, reproduce, and maintain structure (homeostasis).
D) Unicellular organisms are not living.