Please choose the correct ending to complete the given sentence: Health: [header] How to mobilize your spine [title] Find a flat surface, preferably with light padding. [step] A carpeted floor works great. [title] Lie on your back and stretch.

Ending1: [step] Make sure that your head is pointing straight up. [title] Sometimes, deep stretching can be a good idea in order to stimulate your spine. Ending2: [step] You can keep your head down, but if you prefer it, just relax your neck and really focus on your breathing. [title] Get up, stretch, and drink some water. Ending3: [step] Roll your shoulders back and lean forward. [title] Ask someone to gently push your shoulder blades back. Ending4: [step] Imagine that you're being pulled from your feet and the top of your head. This lengthens the spine [title] Tuck your knees into your chest and wrap your arms around your legs.

Answer format: ending1/ending2/ending3/ending4