Which of the following components comprise the Central Nervous System (CNS) in humans?
I. Brain
II. Spinal cord

The correct option is Both I and II.

Explanation:
The human nervous system is divided into two primary parts: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).

1. Central Nervous System (CNS):
The CNS is the main control and processing center of the body. It comprises two major organs:
• Brain: Located inside the skull (cranium), the brain receives sensory information, processes it, and sends out motor instructions. It is responsible for higher functions such as thought, memory, emotion, and coordination.
• Spinal Cord: Protected within the vertebral column (backbone), the spinal cord acts as the primary highway for nerve signals traveling between the brain and the rest of the body. It also controls reflex actions independently of the brain.

2. Peripheral Nervous System (PNS):
The PNS consists of all the nerves that branch off from the CNS (cranial nerves and spinal nerves) to connect the organs, limbs, and skin to the central nervous system.

Since both the brain (I) and spinal cord (II) make up the Central Nervous System, the correct answer is Both I and II.