The suns pole reversals are tied to its

Cycle of sunspots. I hope this helps! I looked up the answer by the way, so no credit to me lol

cycle of the sunspots

Explanation:  This reversal happens every 11 years and is tied to the sun’s cycle of activity,now near it’s peak. The effects of the reversal will ripple throughout the solar system. Every 11 years ,at the sun’s magnetic polarity reverses itself.

Cooking was discovered 1.8 million to 2.3 million years ago.
Pasteurization was discovered in the 12th century.
Fermentation Was discovered a thousand years ago before Christ.
Canning was recently developed. the first one was in the 19th century.
- So the right answer is cooking.