Which letter has the shape of a logistic growth curve that depicts a population limited by a definite carrying capacity? 

A)  S 
B)  L 
C)  J 
D)  M

The logistic growth curve has an S-shape, starting with slow growth, followed by rapid growth, and then tapering off to a plateau as the population reaches its carrying capacity. The carrying capacity represents the maximum number of individuals that can be supported by the environment, and the S-shape of the curve symbolizes how growth becomes limited as the population approaches this capacity. Therefore, the letter S is the best choice that describes a logistic growth curve limited by a definite carrying capacity.