A feminist is reading a chemistry textbook. One line says "All fires require oxygen to burn."

It's because she spotted the letters "xy" together, and XY in chromosomes means "male" as opposed to females, who have two X chromosomes, or XX. It's a joke saying feminists get triggered by all men.

@BlueMetalChick: .... oh...😐

@badazzbasicbich: It's been a meme lately where someone posts a photo of someone looking at a seemingly harmless image, but then finds something contained inside that triggers them. Like one of Bernie Sanders looking at a carton of milk, and he was smiling, until it zoomed in on the words "1%" like 1% fat milk, and it says "#TRIGGERED" with a photo of an angry Bernie.