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: Question: Which of the following structures is not present in animal cells? Answer: cell wall

Answer: A cell wall is not present in animal cells.


Question: Question: What is harmless water vapor, for a powerplant? Answer: steam

Answer: Steam is harmless water vapor, for a powerplant.


Question: Question: Why are continents unable to be pushed down into the mantle by plate boundaries? Answer: buoyancy

Answer:
Continents are unable to be pushed down into the mantle by plate boundaries because of buoyancy.