Final answer:
National parks reduce the human impact on land by preventing human development and restricting activities that could harm the environment.
Step-by-step explanation:
National parks reduce the human impact on land by preventing human development. By designating certain areas as national parks, the government restricts human activities such as building infrastructure or extracting resources in order to protect the natural environment. This helps to preserve ecosystems and maintain the biodiversity of the protected areas. For example, national parks like Yosemite in the United States draw millions of visitors each year while still ensuring the conservation of the park's resources.