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Sushmita Best Answer
Answer: 52-B(hornblende) 53-A(nickel;Ni) In bowen's reaction series, the variation of major elements oxide ultramafic to felsic igneous rock; MgO2, FeO, CaO decreases and SiO2, Na2O, K2O increases. In question given iron-poor basic magma, so for questions no. 52 first mineral to crystallise will be hornblende. And for trace elements, during differentiation of magma the early formed minerals are ultramafic to mafic composition, these minerals incorporated compatible trace elements. Ex: Ni, Co, Sc, Cr. So, correct option should be Ni for question no-53. Compatible trace elements: Trace elements which prefer solid phase during differentiation of magma then trace elements is compatible trace elements.