Respiration is done to breakdown _____ to release energy

Explanation

**Step-by-Step Solution:**

1. **Understanding Respiration**: Respiration is a biological process that occurs in living organisms. It is essential for the release of energy needed for various life processes.

2. **Role of Glucose**: In respiration, the primary substance that is broken down is glucose. Glucose is a simple sugar that is a key source of energy for cells.

3. **Process of Digestion**: Before respiration can occur, food intake happens, and the food is digested. During digestion, complex compounds in food are broken down into simpler forms, one of which is glucose.

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