Choisir is a verb third groupe (as dormir, partir) the verbs -ir are 2nd group when you have = -issons, issez, issent in the three plural "nous, vous, ils/elles) as finir, réunir, maigrir...
Tu choisis une robe longue et des sandales pour le mariage de ta cousine = you choose a long dress and sandals for your cousin's wedding
The cartilage that coats your bones helps with movement. If it's torn or worn, it can leave the rough bone surfaces exposed, resulting in friction in the joint.
