Harry is hospitalized with bacterial pneumonia. When you visit him, his teeth are chattering, his skin is cool and clammy to the touch, and he complains of feeling cold even though his room is quite warm. Explain his symptoms.

his body is fighting off the bacteria

Explanation:

those symptoms are his bodys response to the bacteria, making sure it doesnt keep spreading and keeping him alive.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.