## **Core Concept**
Covalent bonds are a type of chemical bond that involves the sharing of electron pairs between atoms. This sharing leads to a stable molecule where both atoms achieve a more stable electronic configuration, often similar to that of the nearest noble gas. Covalent bonds can be polar or nonpolar, depending on the electronegativity difference between the atoms involved.

## **Why the Correct Answer is Right**
The correct statement regarding covalent bonds involves understanding their nature and characteristics. Covalent bonds are formed when two atoms share one or more pairs of electrons in order to gain a more stable electron configuration. This type of bonding is common in organic molecules and in molecules that are composed of nonmetals.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Without the specific details of option A, we cannot directly address its inaccuracies. However, generally, if an option suggests that covalent bonds are formed by the transfer of electrons, it would be incorrect because that describes ionic bond formation.
- **Option B:** Similarly, without specifics, if option B implies that covalent bonds are only found in metals or are characteristic of metallic bonds, it would be incorrect because covalent bonds are typically associated with nonmetal atoms.
- **Option C:** If option C suggests that covalent bonds are weak and easily broken, it would be misleading. While it's true that covalent bonds have varying strengths, they are generally strong and require significant energy to break.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **covalent bonds** are crucial in the structure of biological molecules such as proteins, carbohydrates, fats, and nucleic acids. Understanding the nature of these bonds is essential for grasping various biochemical processes.

## **Correct Answer:** D. Covalent bonds involve sharing of electrons between atoms.