Symbiosis is a biological term that describes a close and long-term interaction between two different species. This relationship can be beneficial for both organisms, harmful to one, or neutral. There are three main types of symbiosis: mutualism, where both species benefit; commensalism, where one benefits and the other is unaffected; and parasitism, where one benefits at the expense of the other. An example of mutualism is the relationship between bees and flowers. Bees collect nectar from flowers for food while helping to pollinate them, which aids in reproduction. In contrast, an example of parasitism is ticks feeding on the blood of mammals, benefiting from the host while harming it.