Organic compounds exhibit isomerism due to the presence of rigid and directional covalent bonds.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Statement**: The statement claims that organic compounds exhibit isomerism due to the presence of rigid and directional covalent bonds. We need to analyze this assertion.

2. **Covalent Bonds Characteristics**: Covalent bonds are formed when atoms share electrons. These bonds are characterized by their strength (rigidity) and directionality. The rigidity of covalent bonds means they do not easily rotate around the bond axis, while directionality refers to the specific orientation of the orbitals involved in bond formation.

3. **Isomerism in Organic Compounds**: Isomerism occurs when two or more compounds have the same molecular formula but different structural formulas. This can lead to different physical and chemical properties.

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