She came in, ( ) the light on. A: flipping B: flips C: flipped D: flip

It was Cindy who _____ the switch that opened the front gate. A: flip B: flips C: flipped D: flipping

GTP-binding proteins act as _______________: they are in their active conformation when GTP is bound, but they can hydrolyze this GTP to GDP, which releases a phosphate and flips the protein to an inactive conformation.

Questions 5 to 7 will be based on the following news item. Question 5 A: The rocket booster delivers the payload into space. B: The rocket booster burns up on its way back to Earth. C: The rocket booster separates and flips in space. D: The rocket booster comes back to Earth.