Given a scientific passage and an answer, generate a question for the given answer.
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Question: Passage: Plants in the haploid generation are called gametophytes . They form from haploid spores. They have male and/or female reproductive organs and reproduce sexually. They produce haploid gametes by mitosis. Fertilization of gametes produces diploid zygotes. Zygotes develop into the diploid generation. Answer: through mitosis

Answer: How do gametophyte plants form haploid gametes?

Question: Passage: The cell membrane is made up of a phospholipid bilayer, two layers of phospholipid molecules. Notice the polar head group of the phospholipid is attached to the phosphate, and the tails are two fatty acid chains. The head group and tails are attached by a glycerol backbone. Answer: cell membrane

Answer: What basic cell structure is made up of a phospholipid bilayer and two layers of phospholipid molecules?

Question: Passage: Testing a hypothesis requires data. Data can be gathered by observations or by experiments. Answer: data

Answer:
What do you require to test a hypothesis?