Answer:
The correct answer will be option- sagittal plane or anterior–posterior plane
Step-by-step explanation:
Flexion and extension are the movements of the body which involves the anterior or posterior movements of the limbs or the body.
Flexion is the anterior or froward movement of the body part whereas the Extension is the movement of the body parts in the posterior or backward direction.
Therefore the flexion and extension movement takes place in the anterior-posterior plane also known as the sagittal plane and thus is the correct answer.