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

Example Input: Passage: Cells are the tiny building blocks of living things. They couldn't be discovered until the microscope was invented. The discovery of cells led to the cell theory. This is one of the most important theories in life science. Answer: cells
Example Output: What are all living things made of?

Example Input: Passage: Mutations have many possible causes. Some mutations occur when a mistake is made during DNA replication or transcription. Other mutations occur because of environmental factors. Anything in the environment that causes a mutation is known as a mutagen . Examples of mutagens are shown in Figure below . They include ultraviolet rays in sunlight, chemicals in cigarette smoke, and certain viruses and bacteria. Answer: mutation
Example Output: What is it called when a mistake occurs in dna replication.

Example Input: Passage: Fossils are preserved remains or traces of organisms that lived in the past. Most preserved remains are hard parts, such as teeth, bones, or shells. Examples of these kinds of fossils are pictured in Figure below . Preserved traces can include footprints, burrows, or even wastes. Examples of trace fossils are also shown in Figure below . Answer: fossils
Example Output:
Preserved remains or traces of organisms that lived in the past are known as what?