Which graph below best represents exponential growth?

Which graph below best represents exponential decay?

Which equation below shows an exponential equation?

Each person with influenza can infect several other people. What would a graph of the total number of new infections over time show?

After consumption, the kidneys eliminate a percentage of caffeine from the bloodstream. What would a graph of the concentration of caffeine in the bloodstream over time show?

An ice-cream shop plans to open 4 new locations each year. What would a graph of the shop openings over time show?

Riding a wave of popularity, the number of frozen yogurt shops in a county has doubled each year for four years. What would a graph of store openings over time show?

In a nuclear chain reaction, breaking one atom releases particles, each one of which can trigger another atom to break. What would a graph of new reactions over time show?

A factory emits 50 gallons of pollutant-contaminated water each day into a lake. What would a graph of the pollutant concentration of the lake over time show?