Final answer:
Sydney treated her sore knees using ibuprofen for systemic pain relief and a topical ointment for local pain relief.
Step-by-step explanation:
Sydney treated her sore knees by taking ibuprofen, an oral pain reliever, which had a systemic effect on her body. This means that the ibuprofen was absorbed into her bloodstream and circulated throughout her body, providing overall pain relief. Additionally, she rubbed a topical ointment on the area, which had a local effect. This means that the ointment worked directly on the knees, providing targeted pain relief.
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