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: Expansion of a gas into a vacuum is irreversible because the external pressure is measurably less than the internal pressure of the gas, and no states of what exist? Answer: equilibrium
Expansion of a gas into a vacuum is irreversible because the external pressure is measurably less than the internal pressure of the gas, and no states of equilibrium exist.

Question: What is the term for when deep ocean water rises to the surface? Answer: upwelling

Upwelling is the term for when deep ocean water rises to the surface.