When was blinking invented?

no googling (unless you really get stumped)

What would lead a historian to consider two events to have a relationship of correlation rather than causation?

Which best describes the effect of europe on aboriginal peoples?

You are given the first four terms of an arithmetic sequence. why might you use a recursive formula? why might you use an explicit formula? under what conditions might a recursive formula be preferred over the explicit formula? under what conditions might an explicit formula be preferred over the recursive formula? pleasss ! sorry if it's a long question: (