Fill in the blank below: in a digestive system, digestion takes place outside of the cells in a series of tubes. food enters one opening and food remnants exit out of a different opening. examples of organisms with this type of digestive system include you, dogs, horses, spiders and earthworms.

Gastrointestinal? I believe.

The answer is 
Complete

For example, the wing of a butterfly and the wing of a bird are analogous; the two types of wings share a common function (and therefore both are called wings), but the bird wing and insect wing did not arise from a common original ancestral structure that become modified through evolution into bird wings and butterfly ...