Ze lijkt op haar moeder. (She resembles her mother.)
lijken takes "op" (lijken op = to resemble). Example: Ze lijkt op haar moeder. (She resembles her mother.)
Ze lijkt op haar moeder. — She resembles her mother. The preposition op is fixed, so it doesn't change with the sentence.
Fixed prepositions come up all over the A2 exam. The platform drills them in real exam tasks, AI-graded across all five DUO sections.