**Core Concept**
The cervical spine is composed of seven vertebrae, each with unique characteristics that distinguish them from the other cervical vertebrae. Understanding the anatomy of the cervical spine is crucial for diagnosing and managing various spinal disorders.

**Why the Correct Answer is Right**
The cervical vertebra that lacks a body and a spinous process is the C7 vertebra, also known as the vertebra prominens. This vertebra is characterized by its distinctive keel-shaped posterior arch, which gives it a prominent appearance at the base of the neck. The absence of a body and spinous process in C7 is due to its unique embryological development, where the posterior elements of the vertebra form from the posterior sclerotome, while the body forms from the anterior sclerotome. As a result, C7 has a distinctive posterior arch that gives it a different appearance compared to the other cervical vertebrae.

**Why Each Wrong Option is Incorrect**
**Option A:** The C1 vertebra, also known as the atlas, has a body and a spinous process, although it is highly modified and serves as the first cervical vertebra that allows for rotational movement of the head.
**Option B:** The C6 vertebra has a body and a spinous process, which is similar to the other cervical vertebrae except for C7.
**Option C:** The C5 vertebra has a body and a spinous process, similar to the other cervical vertebrae except for C7.

**Clinical Pearl / High-Yield Fact**
When examining a patient's cervical spine, the presence of a prominent posterior arch at the base of the neck is a characteristic feature of the C7 vertebra. This can be useful in diagnosing and managing various spinal disorders, particularly those affecting the cervical spine.

**Correct Answer:** C