disrupting something from reaching something else decreases the availability of that something & smoke from volcanic eruptions can disrupt sunlight from reaching earth 's surface ->  smoke from volcanic eruptions can decrease the availability of sunlight  smoke from volcanic eruptions can decrease the availability of sunlight & as the availability of sunlight decreases , the ability of producers to produce food decrease ->  smoke from volcanic eruptions can decrease the food produced by the producers by decreasing the availability of sunlight  smoke from volcanic eruptions can decrease the food produced by the producers by decreasing the availability of sunlight & food is a kind of resource -> smoke from vocanic eruptions can decrease resources in an area by decreasing the availability of sunlight