a) State "Gauss' competitive exclusion principle".
b) Mutualism is a method of population interaction. Explain with examples

Hint:Gause’s law in ecology refers to when two species compete for limited resources, the population cannot be stable for both species. Mutualism is an interaction between the species which helps each other with nutrition where their needs are complementary like they don’t compete for the same resource.

Complete answer:The competitive exclusion principle is also known as Gause’s law. The law states that when two species compete for one limited resource, the population cannot coexist with the same population growth or same growth status. When one species has even the slightest chance of having an advantage over another, the population starts dominating the other species.
Thus, the other species cannot survive and starts declining. This leads to the extinction of the weaker species or can have ecological shifts. The competition in the species happening between the same species is known as intraspecific and in between different species is known as interspecific.
Mutualism is a positive interaction where the species are both benefited from their presence in the same area. It is also called symbiosis. The mutualism can be facultative or obligatory.
Obligatory mutualism includes they compulsorily need each other for survival. The examples include lichens (algae and fungi) and Rhizobium.
Facultative mutualism includes the survival of species even when they are not in symbiosis. The examples include the interaction between a hermit crab and sea anemone.

Note: The mutualism shows that the gauss law is true as they coexist happily when they are not competing with each other for the same resources. The population of the species remains stable and has no negative effects.