Fact 1: If a planet becomes too hot then that planet cannot sustain life.

Fact 2: Mercury is close to the Sun, and is extremely hot.

Given the two facts above, answer the question "Mercury cannot sustain life because it is" with the following options: 
- too close to the Sun
 - harmful substances
 - dormant state
 - major threat to health
 - too cold
 - has little gravity
 - scarce resources
 - too small


 

 too close to the Sun        