A cooperative observer is someone who helps scientists and researchers by providing information about the weather or environmental conditions. They might tell the scientists things like how hot or cold it is, how much rain has fallen, or how much snow is on the ground. This information helps the scientists understand what is happening in the environment and can help them make better predictions about what might happen in the future. The cooperative observer is like a helper or assistant to the scientists, and their information is very important in helping us understand and predict changes in the environment.