From the given options,identify the correct combination of population interactions that correspond to the symbols given here.

The graph below shows the changes in two populations of herbivores in a grassy field. $A$ possible reason for these changes is that

Why do parasites exhibit parasitism?

Select the appropriate option for the relationship between $Yucca$ and the moth.

Which of the following statements regarding species interdependence are true?
$I.$ An association of two species where one is benefited and the other remains unaffected is called mutualism.
$II.$ An interspecific association where both partners derive benefit from each other is called commensalism.
$III.$ $A$ direct food relation between two species of animals in which one animal kills and feeds on another is referred to as predation.
$IV.$ $A$ relationship between two species of organisms where both partners are benefited from each other is called symbiosis.

Choose the incorrect sentence.