Fact 1: Better senses have a positive impact on an animal 's survival.

Fact 2: Dogs are social animals, but they have an acute sense of smell.

Given the two facts above, answer the question "A better what can have a positive impact on a dog's survival?" with the following options: 
- food and shelter
 - sensory neurons
 - stamina
 - haircut
 - sense of smell
 - sense of touch
 - fur pattern
 - prolactin release


 

     sense of smell    