In cities, there are many buildings, roads, and people. But even though cities have lots of cement and people, nature is still a part of it! Urban ecologists study how animals and plants live in cities. They want to understand how the city changes the environment and how animals and plants adapt to the city life. For example, some birds make nests on top of buildings instead of in trees. People can help urban ecologists by making gardens in the city and planting more trees, so animals have a place to live.