Fatty acids enter cellular respiration as two-carbon fragments.

Answer

### Step-by-Step Solution:

1. **Understanding Cellular Respiration**: Cellular respiration is the metabolic process through which cells convert glucose and other organic molecules into energy, primarily in the form of ATP (adenosine triphosphate).

2. **Role of Fatty Acids**: Fatty acids are a type of lipid that can also be used as an energy source. They undergo a process called beta-oxidation to be converted into usable forms for cellular respiration.

3. **Conversion to Acetyl Coenzyme A**: During beta-oxidation, fatty acids are broken down into two-carbon fragments. These two-carbon fragments are converted into a molecule called acetyl coenzyme A (acetyl CoA).

4. **Entry into the Krebs Cycle**: Acetyl CoA is the key molecule that enters the Krebs cycle (also known as the citric acid cycle or TCA cycle). This cycle is a series of chemical reactions used by all aerobic organisms to generate energy.

5. **Formation of Citric Acid**: In the Krebs cycle, acetyl CoA combines with a four-carbon molecule (oxaloacetate) to form a six-carbon compound known as citric acid (or citrate). This reaction is catalyzed by the enzyme citrate synthase.

6. **Conclusion**: Therefore, the statement that fatty acids enter cellular respiration as two-carbon fragments is correct, as they are converted into acetyl CoA, which is a two-carbon molecule that enters the Krebs cycle.