In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.

Question: What do scientists think are the oldest eukaryotes? Answer: protists
Scientists think protists are the oldest eukaryotes.

Question: Which observation demonstrates that light waves travel much faster than sound waves? Answer: An exploding firework is seen before it is heard.
An exploding firework is seen before it is heard observation demonstrates that light waves travel much faster than sound waves.

Question: What determines whether a volcanic eruption will be explosive or not? Answer: thickness of magma

The thickness of magma determines whether a volcanic eruption will be explosive or not.