What is the greatest threat to the world's national parks? 

A)  human activities in nearby areas 
B)  lack of funding 
C)  uncontrolled populations of prey because of the decline in predators 
D)  pollution

Human activities in nearby areas, such as urban and industrial development, tourism, and resource extraction, can have negative impacts on national parks. These activities can introduce pollution, noise, and light pollution, as well as disrupt wildlife habitats and migration patterns. Furthermore, they can also lead to increased infrastructure needs in the parks and put pressure on their limited resources. As a result, mitigating the negative impacts of human activities continues to be a significant challenge for park managers and conservationists. While lack of funding, uncontrolled prey populations, and pollution can also pose significant threats to national parks, human activities are likely the greatest and most pervasive threat to their long-term health and survival.