1
2
3
4
5
6
barbule
shaft
hooklets
None of the above
Only one
More than five
More than ten
More than twenty
Tobogganing or sledding
Swimming
Floating
Singing
Snowshoeing
Soft feathers at the bottom of a feather
The stiff hair-like parts of a feather
The central shaft of a feather
Kerosene
Keratin
Krypton
Kudzu
The shape of a birds wing is the reason they can fly?