Examine each of the situations below to determine whether it should be modeled with a linear function or an exponential function.

The population of a certain sea turtle grew by
19% from year to year.

A certain type of single-cell amoeba reproduces by dividing once each day.

The total paid for a meal in a restaurant,
including tip, is found by multiplying the billed
amount by 120%.

Pablo contributes $5 of his allowance to his
piggy bank each week.

To cook a stuffed turkey, a cookbook
recommends a cooking time of 90 minutes
plus 15 minutes per pound.

Samuel owes his brother $100 and promises to
pay half of what he owes each week until the
debt is paid