What is dependent and independent variable in " will birds with shorter or longer wings fly faster ? ?

Independent: the bird 

dependent:  with shorter or longer wings fly faster

The independent Varible is birds The dependent variable is how fast the birds fly

If we perceive our body as too fat even though our body is not we might diet until we think we aren't fat and if we perceive our body as too thin we might binge eat until we think we are average weight ( not too thin and not too fat )