In someone who has cystic fibrosis the person’s mucus becomes thick. Figure 2 shows how, in a healthy person, cells at the lung surface move chloride ions into the mucus surrounding the air passages. The movement of chloride ions causes water to pass out of the cells into the mucus.
Explain why.

sound moves fastest in solids because the molecules are tightly packed and it allows sound to vibrate

i believe it's c. the trait for large beaks will be passed on to future generations through natural selection.

since eventually smaller beaks would have to find another source of food or even eventually just die out from the lack of food.

answer; heredity;