A student is studying the levels of organization in living things and creates a table to give examples of the different levels.
 Level of organization
 cell
 tissue
 organ
 organ system
 organism
 ecosystem
 Example
 red blood cell
 digestive system
 wetland
 Which of these should the student write as an example of the organism level of organization?
 Choose the correct answer.
 O human
 O stomach
 O connective tissue
 O food, water, and air