Fact 1: Some arthropods have special excretory structures.

Fact 2: Crustaceans are, like insects, arthropods.

Given the two facts above, answer the question "Crustaceans and insects have what special structures?" with the following options: 
- the eyes
 - a cuticle
 - internal
 - excretory
 - invisible
 - Chlorophyll
 - fur and fat
 - muscled


 

    excretory     