Glycolysis/fermentation forms two 2 ATP molecules per glucose molecule.

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Glycolysis**: Glycolysis is the first step of cellular respiration that occurs in the cytoplasm of all living organisms. It does not require oxygen, making it an anaerobic process.

2. **Process of Glycolysis**: During glycolysis, one molecule of glucose (a six-carbon sugar) is partially oxidized. This process results in the production of two molecules of pyruvate (a three-carbon compound).

3. **ATP Production**: The net gain from glycolysis is two ATP molecules per glucose molecule. This is because four ATP molecules are produced during the process, but two ATP molecules are consumed, resulting in a net gain of two ATP.

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