Answer:
b. a phosphate is removed
Step-by-step explanation:
ATP is a molecule that stores and releases energy. When a phosphate group is removed from ATP, the energy is released and ATP is converted to adenosine diphosphate (ADP). This process is called hydrolysis.
The energy released from ATP hydrolysis can be used to power other reactions in the cell. For example, it can be used to transport ions across cell membranes, to contract muscles, or to synthesize proteins.