Fact 1: Many plants respond to the days growing shorter in the fall by going dormant.

Fact 2: After the autumnal equinox, days gradually shorten in the Northern Hemisphere.

Given the two facts above, answer the question "Many plants go dormant during the  " with the following options: 
- heat or cold
 - earth's revolving
 - autumnal equinox
 - colder and wetter
 - It helps them survive
 - cloudy and rainy weather
 - Plant growth is reduced
 - fire conditions


 

   autumnal equinox      