Which is a resource that the National Park Service manages? memorials
wildlife refuges
ecosystems
endangered species

A decrease in resources and loss of habitat.

Explanation:

According to Science magazine, most living things have already been affected by climate change, especially global warming. US researchers have found that about 82% of ecological processes (genetic diversity and migratory processes) have already changed as a result of abnormal temperatures. Species have undergone genetic changes, with changes in their physical characteristics. In addition, changes in their migratory processes have led these animals to move to previously unexplored places. These constant migratory processes occur due to the greatest effects of climate change on populations, which are: diminishing resources and habitat loss.