Answer
Temperature is a function of altitude
Fuel consumption is a function of speed
Wi-Fi signal strength is a function of distance
Work Step by Step
Temperature is a function of altitude - For example, when we go up in the mountain, temperature decreases based on the altitude. Roughly saying, temperature changes by $10°C$ per kilometer.
Fuel consumption is a function of speed - A car's consumption of fuel varies based on the speed of the car.
Wi-Fi signal strength is a function of distance - Almost all of us experience this in our everyday life. Wi-Fi signal gets weak when we get far from Wi-Fi router and it gets stronger when we get closer. So the signal strength is function of distance from the router.
