Answer:
Smart phone sales since 1990:- linear function
Half life of a pesticide :- exponential function
Step-by-step explanation:
Linear function can be applicable in almost any situation where there is an unknown quantity can be represented by a linear equation, like figuring out income over time, calculating mileage rates, or predicting profit, therefore smart phone sales since 1990 can be model with linear function
Exponential functions can be applicable in social, scientific, or personal finance situations such as population growth, radioactive decay and half life, therefore half life of pesticide can be model with exponential function.