Fact 1: If seeds stick to the fur of an animal then that seed will be transported by the animal.

Fact 2: Burrs and some other seeds have tiny barbs that hook on to cat fur.

Given the two facts above, answer the question "What is transported by sticking to the fur of an animal?" with the following options: 
- burrs
 - food
 - keratin
 - caviar
 - A virus
 - fish
 - eggs
 - lipids


 

 burrs        