In which of the following species interactions does one organism benefit from the interaction while the other organism's fitness is unaffected, neither benefiting nor suffering?
1
Mutualism, where both species benefit and their fitness is increased
2
Commensalism, where one species benefits and the other is unaffected
3
Parasitism, where one species benefits at the expense of the other
4
Competition, where both species suffer a decrease in fitness due to resource scarcity