Final answer:
A) Carrying capacity
The sum of all limiting factors on population growth is known as the carrying capacity, which is the sustainable maximum population size for a given environment.
Step-by-step explanation:
The sum of all limiting factors on population growth is referred to as the carrying capacity of an environment. The carrying capacity is the maximum population size that a particular area can support sustainably without the habitat being degraded.
When resources are abundant, populations often experience exponential growth, but as resources become scarce due to the increasing population, growth rates decline, eventually reaching the level called the carrying capacity.
This shift from exponential to logistic growth, marked by a leveling off, indicates that the population has reached the size that the environment can consistently support given the available resources.