How do you determine if a relation is a function ​

Which of the following is the result of expanding

Annabelle's homework is 75% it took her three hours how long should she estimate it will take her to complete her homework.

Rachel is studying the population of a particular bird species in a national park. she observes every 10th bird of that species that she can find in the park. her conclusion is that the birds living in the park who belong to that species generally feed on insects. rachel's sample is . based on the sample she picked, rachel's generalization is