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.

[Q]: Question: What is the most abundant type of biological entity on the earth? Answer: viruses
[A]: Viruses are the most abundant type of biological entity on the earth.

[Q]: Question: Which of the following has changed over the last 200 years primarily due to human activity? Answer: the composition of the atmosphere
[A]: The composition of the atmosphere has changed over the last 200 years primarily due to human activity.

[Q]: Question: What type of cell has negative anode is positive cathode? Answer: voltaic cell
[A]:
Voltaic cell type of cell has negative anode is positive cathode.