Please choose the correct ending to complete the given sentence: Home and Garden: [header] How to stop cracking your knuckles [title] Understand what causes the cracking sound. [step] When you crack your knuckles, you are manipulating certain joints in the body in a manner that promotes the release of gas (currently thought to be primarily nitrogen) from synovial fluid. Synovial fluid exists within synovial joints, and its function is to reduce friction between cartilage.

Ending1: When a knuckle is cracked, the gases dissolved within the synovial fluid are compressed and form of a bubble. This bubble then bursts, making that familiar popping sound as it does so. Ending2: This friction is a result of the formation of dialogal cell walls. Learning how to break these spacial and internal tissues can help you prevent cracking your knuckles, which can cause swelling. Ending3: A lingering gas behind your joints may actually be caused by the spreading of the fluorocarbon builds up inside of these joints. For example, a building might have one joint that was once home to a high density steel building. Ending4: This is the reason that cracking knuckles is so important, for persons with weakened gums. This occurs due to the inferior receptors in the joints.

Answer format: ending1/ending2/ending3/ending4