Questions: Where are cartilaginous joints commonly found?

The answer is the fourth one: spine and ribs.

Explanation for each option:

1. Fingers and toes: These joints are typically synovial joints, which allow for a wide range of motion.
2. Ankles and wrists: These are also primarily synovial joints, which provide flexibility and movement.
3. Hips and shoulders: These are ball-and-socket synovial joints, known for their extensive range of motion.
4. Spine and ribs: Cartilaginous joints are commonly found here. The intervertebral discs between the vertebrae in the spine and the costal cartilages connecting the ribs to the sternum are examples of cartilaginous joints.
5. Knees and elbows: These are hinge synovial joints, which allow for bending and straightening movements.

Summary: Cartilaginous joints are commonly found in the spine and ribs, where they provide a combination of stability and slight movement.