Final answer:
Using up available land for shelter at the expense of land for food production is an example of how land as a limiting factor determines carrying capacity with growing human populations.
Step-by-step explanation:
Land is a limiting factor that determines the carrying capacity of an environment because it provides the necessary resources for life, such as space for shelter and production of food. As the human population grows, the statement 'We are using up available land and converting land for food into land for shelter' directly reflects how land use affects carrying capacity. With more individuals, the demand for housing increases, often at the cost of agricultural land, which in turn affects food supply—a critical resource for sustaining the population. The conversion of fertile land to urban areas can therefore be seen as an activity that could reduce the carrying capacity of the environment if not managed sustainably.