What is the best biological explanation for why the population stayed below the carrying capacity between days 100 and 160?

• A. Overcrowding before day 100 caused the birth rate to decrease and the death rate to increase, and it took another 60 days for the relative rates to stabilize.
• B. Overshoot carrying capacity earlier caused a crash and then recovery.
• C. The carrying capacity increased due to resource availability.
• D. A disease reduced population size temporarily.

Answer: (C)

Carrying capacity is not fixed; it depends on resource availability in the environment. If resources become more abundant, the carrying capacity rises, meaning more individuals can be supported long-term. The population may stay below this new, higher carrying capacity for some time because the size has not yet fully adjusted to the increased limit—birth rates can rise and population growth can accelerate, but there is a lag as numbers slowly increase toward the new K. So, the period between days 100 and 160 being below the carrying capacity is best explained by a rise in resources that increases carrying capacity, not by a crash, a temporary disease effect, or an unchanged K.