The large ship carried british passengers across the ocean to america. whats the proper adjective in the sentence?

A proper adjective is an an adjective derived from a proper noun that is also typically capitalized. (Proper nouns are the origin of proper adjectives.)

In this case, if Britain is a proper noun, then British is the proper adjective. So the answer to your question should be British.

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answer; ///it examines the interaction between genetics and culture in shaping human biology;

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