Answer: b. All living things are made of cells.
Explanation:
A cell is the smallest basic unit of life that is capable of independent functionality. A cell therefore cannot be made up of other cells because that would imply that there is a unit of life that is smaller than cells.
Cells are instead made up of organic molecules like protein and carbohydrates and when cells work together to achieve a common goal, they form a tissue. Tissues are the ones made up of cells not cells made up of other cells.
