Which of the following is the middle layer in the root apical meristem that gives rise to the cortex?

Periblem

The correct answer is Option (1)- Periblem

The middle layer in the root apical meristem that gives rise to the cortex is periblem.

Here's a breakdown of the root apical meristem layers:

• Dermatogen: The outermost layer, responsible for the root cap (protects the tip)
• Periblem: The middle layer, differentiates into the cortex (provides support and storage)
• Plerome: The innermost layer, develops into the vascular tissue (transports water and nutrients)

Calyptrogen is sometimes referred to as a separate layer in some classifications, but it's a sub-layer of the dermatogen specifically responsible for root cap formation.