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.
Answer;
-The third stage fever
Explanation;
-Fever, also referred to as pyrexia and febrile response, involves having a temperature above the normal range (above 37.5 or 38.3 °C) due to an increase in the body's temperature set-point (36.5–37.5 °C). This increase in set-point temperature triggers increased muscle contractions and causes a feeling of cold.
-The first stage of a fever is marked by headache and body aches, the second stage is marked by the chills, and the third stage is the flush state. The fourth stage is defervescence.