Answer:
The food type changes in a given environment, then the amount of each type of bird beak will changes as birds with beaks more suited to the available food will consume more successfully over time. The independent variable of the lab is the type of food that is available to the birds.
I also believe the answer is A.
The first one, cause their trying to make it a positive way to reinforce. Which just means their trying to fix something again
95% sure it is answer B) Detect the electrical discharges of prey in the sand using small pits on it's bill, crush the food with grinding pads on the top and bottom of it's bill (they don't have actual teeth), and webbed feet.
I did some quick research and it had all of those things.
Hope this helps.
Answer: B is an unsaturated fatty acid