Contour: Gives the bird its stream line shape.
<span>Down feathers: Keeps the bird warm.</span>
Wind because its not mechanically eroding them..
Answer:
combining plant protein sources to achieve a better amino acid
Explanation:
Bringing it all together. Protein complementation is combining plant protein sources to achieve a better amino acid balance than either would have alone. Because of differences in amino acid make-up, when plant sources are combined, the strengths of one make up for the deficiencies in another