The correct answer is - the release of methane from thawed permafrost.
In the past decade it has been noticed that the levels of methane are increasing in the atmosphere, and the biggest ''producer'' of this methane is the melting permafrost. There's huge amounts of methane trapped underground bellow the permafrost. But the permafrost is melting because of the global worming, so the methane is free to come out and go up in the atmosphere.
2009 is the year that the population of zebras and lions is the highest
The stem cell will go through mitosis to cause the differentiated cells it produces to also be cancerous; option A
<h3>What is mitosis?</h3>
Mitosis is a process in cells which accounts for the production of new cells by the division of cells.
Cancer results when there is abnormal growth and division of cells.
Therefore, mitosis occurs or stem cells to become cancerous.
Learn more about mitosis at: brainly.com/question/19058180
#SPJ1