Which of the following statements about exponential growth curves is true?
a. exponential growth curves are common for r-selected species.
b. exponential growth curves show fast growth rates followed by slow growth rates.
c. no organisms in nature experience exponential growth rates.
d. exponential growth curves are s-shaped.

The correct option is A.

Exponential growth curve is a type of curve that is obtained when a resource is abundant for a particular population of specie. In this case, the growth rate of each individual in the population remain the same and this makes the population to grow rapidly and increase in size. Exponential growth curve is J shaped and is usually found in R selected species. R selected species are those species that have short life span and high rate of reproduction. An example of this is mosquito.

primary succession begins with a bare rock and ends with a forest secondary succession begins after a natural disaster where there is a temporary setback after a forest fire or local destruction, but the surrounding area can fill in