The growth rate of a population that has a limited food supply will most likely be a) exponential. b) logistic. c) natural. d) random.

Correct B) Logistic

 There are four growth phases which are observed in bacteria, these are lag phase, log phase or exponential phase and death phase.

Lag phase is the period when bacteria is adjusting to the environment, under this phase bacteria is adopting to the new environment and preparing essential enzymes which are necessary for the growth.

In the log phase, the bacterial population grow in a logarithmic fashion. As the bacteria  grow, the bacteria consumes all the available nutrients and produce waste products.

When the nutrient supply is depleted, and because of release of toxic waste product  the growth rate enters a stationary phase in which the number of viable bacteria cells stars depleting which will lead to a death phase.  

i believe the correct answer is d

the sphincter muscles at the end of the digestive tract is the anus.