Step 1: Understanding the Concept
Inside the cell, food such as glucose is oxidised step by step and the energy is trapped as ATP.
Step 2: Name of the process
This intracellular oxidation is cellular respiration.
Step 3: Compare
Breathing is only the intake and output of air. External and internal respiration are exchanges of gases at the lungs and at the tissues.
Final Answer:
The process is cellular respiration.
\[ \boxed{\text{(B) }\text{cellular respiration}} \]