Year 12 exam help

[Rose165]

Hey,
I've got my final exam coming up and there is one particular question in a previous exam that has completely thrown me out.
It talks about how birds and butterflies use wings to fly through the air and then asks what it is an example of
a) Analogous Structures
b) Homologous Structures
c) Continuous Structures
d) Discontinuous Structures
I understand the answer is a) but what are Continuous and discontinuous structures? I've googled and looked in text books but it keeps coming up with continuous and discontinuous variations??
HELP!

[Gavin]

Continuous and discontinuous structures have no meaning in evolutionary biology. They have only been offered as options for those who need to guess at the answer.

[Rose165]

Oh ok. Thanks heaps

[wpseofriendly]

It means it was a trick question.