Questions: 3. Which of the following lists the layers of the meninges in the correct order from innermost to outermost? a. Pia mater, arachnoid mater, dura mater b. Dura mater, pia mater, arachnoid mater c. Arachnoid mater, dura mater, pia mater d. Pia mater, dura mater, arachnoid mater

The answer is the first one (a): pia mater, arachnoid mater, dura mater.

Explanation for each option:

a. Pia mater, arachnoid mater, dura mater - This is the correct order of the meninges from innermost to outermost. The pia mater is the delicate innermost layer that directly covers the brain and spinal cord. The arachnoid mater is the middle layer, and the dura mater is the tough outer layer.

b. Dura mater, pia mater, arachnoid mater - This order is incorrect. The dura mater is the outermost layer, not the innermost.

c. Arachnoid mater, dura mater, pia mater - This order is incorrect. The arachnoid mater is not the innermost layer, and the dura mater is not the middle layer.

d. Pia mater, dura mater, arachnoid mater - This order is incorrect. While it starts correctly with the pia mater, the dura mater should be the outermost layer, not the middle one.

In summary, the correct order of the meninges from innermost to outermost is pia mater, arachnoid mater, dura mater.