C. But see the answer under C. Apparently C is the accepted answer.
Explanation:
A. Not A.I don't think that's a problem for gulls especially on beaches.
B. Not B. Their feather do not look like they need much help in keeping their feathers attached when in flight.
C. This is not really the answer, but it is the best answer of these 4. The actual answer is that the bones are porous for better air intake which provides more oxygen and hence they are better able to fly.
D. Not D. Food has nothing to do with the problem. Birds get an adequate amount of food without their wings being porous. See the answer for C.
Solids-atoms vibrate in place, there is a definite shape/volume; Liquids-atoms slide around, there is a definite volume only; Gases-atoms are spread far apart, with no definite shape/volume. Hope this helps.
<span>The genetic term used to describe an observable trait is phenotype. More specifically phenotype is the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.</span>
