Given a scientific passage and an answer, generate a question for the given answer.

Passage: Membranes Biological membranes surround cells and serve to keep the insides separated from the outsides. They are formed of phospholipid bilayer1 s, which by definition are a double layer of fatty acid2 molecules (mostly phospholipid3 s, lipids containing lots of phosphorus). Proteins4 serve very important functions in cellular membranes. They are active transports in and out of the cell, acting as gatekeepers. They relay signals in and out of the cell. Proteins are the site of many enzymatic reactions in the cell, and play a role in regulation of cellular processes. Answer: biological membranes
What is it that surrounds cells and serve to keep the insides separated from the outsides?

Passage: Centrioles are rod-like structures made of short microtubules. Nine groups of three microtubules make up each centriole. Two perpendicular centrioles make up the centrosome . Centrioles are very important in cellular division, where they arrange the mitotic spindles that pull the chromosome apart during mitosis. Answer: centrioles
What are the rod-like structures made of short microtubules that play an important part in cellular division?

Passage: Jaws Beach in Maui, Hawaii has legendary waves. The largest waves come when winds are very strong, usually in the winter. The rocks and reef offshore magnify the size of the incoming wave energy. Cowabunga!. Answer: winter
What season do the largest waves for surfers typically come?