Step 1: Understanding the longest cell in the human body.
Nerve cells, or neurons, are the longest cells in the human body. Some neurons, like the sciatic nerve, can extend from the spinal cord to the toes, reaching lengths of over a meter.
Step 2: Explanation of incorrect options.
- Muscles are composed of fibers but are not single cells.
- Blood cells are among the smallest cells.
- Heart cells are specialized muscle cells but are not the longest.