Fact 1: Most invertebrates have a more complex nervous system.

Fact 2: Insects are the most common invertebrates.

Given the two facts above, answer the question "What crawls and is known to have a complex nervous system? " with the following options: 
- fur seals
 - Insects.
 - mammals
 - animals
 - a fish
 - humans
 - bees
 - ducks


 

  Insects.       