You are presented with the question "The runaway greenhouse effect present on Venus makes what unlikely?" and the following answer choices: 
- carbon in the atmosphere
 - bloom time
 - Animal survival
 - robotic landers
 - sustainable life
 - Plant reproduction
 - population movement
 - sunlight at the surface

Now knowing that if a planet becomes too hot then that planet cannot sustain life and venus is thought to be hot because of the runaway greenhouse effect, choose the best answer.


 

     sustainable life    