In biology, a<unk>  is a group of organs that work together to perform a certain task. Common<unk> s, such as those present in mammals and other animals, seen in human anatomy, are those such as the circulatory<unk> , the respiratory<unk> , the nervous<unk> , etc.
A group of<unk> s composes an organism, e.g. the human body.
Biological system
Human cognition
Mental function
Gastrointestinal physiology
Coagulation
Drug metabolism
Human body
Mental Health