Which of the following exhibits parasitism on the stem of a plant?

Commensalism is the interaction in which

Territoriality occurs as a result of

Even a plant species,which makes its own food,cannot survive alone; it needs soil microbes to breakdown the $A$ matter in soil and return the $B$ nutrients for absorption. And then,how will the plant manage pollination without an animal agent? It is obvious that in nature,animals,plants and microbes cannot live in $C$ but interact in various ways to form a biological community. Choose the correct option for $A, B$ and $C$.

An association of two species where both the partners derive mutual benefit from each other is known as:

Moderate grazing in grasslands by herbivores is a/an .....