Select the true statement :

Options

A. glycolysis produces equal numbers of ATP molecules regardless of the presence or absence of oxygen
B. more ATP molecules are produced per molecule of glucose when glycolysis occurs in aerobic conditions
C. more ATP molecules are produced per molecule of glucose when glycolysis occurs in anaerobic conditions
D. none of the above are true

Explanation

To determine the true statement among the options provided, we need to analyze each statement based on our understanding of glycolysis, aerobic respiration, and anaerobic respiration.

### Step-by-Step Solution:

1. **Understanding Glycolysis**:
- Glycolysis is the first step in the breakdown of glucose, occurring in both aerobic and anaerobic conditions. It converts one molecule of glucose into two molecules of pyruvate, producing a net gain of 2 ATP molecules regardless of the presence or absence of oxygen.

2. **Analyzing the Statements**:
- **Statement 1**: "Glycolysis produces equal number of ATP molecules regardless of the presence or absence of oxygen."
- This statement is **true** because glycolysis yields 2 ATP molecules whether oxygen is present (aerobic) or absent (anaerobic).

- **Statement 2**: "More ATP molecules are produced per molecule of glucose when glycolysis occurs in the aerobic condition."
- This statement is **false** because glycolysis itself only produces 2 ATP molecules. The additional ATP produced in aerobic respiration comes from subsequent processes (Krebs cycle and electron transport chain), not from glycolysis alone.

- **Statement 3**: "More ATP molecules are produced when glycolysis occurs in the anaerobic condition."
- This statement is also **false**. Similar to statement 2, glycolysis produces the same 2 ATP molecules in both conditions. Anaerobic respiration does not yield more ATP than aerobic respiration; it yields less overall ATP.

3. **Conclusion**:
- The only true statement is **Statement 1**: "Glycolysis produces equal number of ATP molecules regardless of the presence or absence of oxygen."

### Final Answer:
The true statement is: **"Glycolysis produces equal number of ATP molecules regardless of the presence or absence of oxygen."**