Question

which disturbance would result in primary succession?
○ harvesting wheat by using a combine harvester at the end of the growing season
○ controlled burning to stimulate the growth of forest trees such as sequoia
○ the formation of surtsey, a volcanic island off of the southern coast of iceland
○ the effect of a large herd of elephants on the grasses and shrubs in an area

Explanation:

Primary succession occurs on newly formed or barren land with no soil (e.g., volcanic islands, retreating glaciers). The formation of Surtsey (a volcanic island) starts with no soil or existing life, so it initiates primary succession. Harvesting wheat (agricultural, soil/life present), controlled burning (secondary, soil/life remains), and elephant herds (secondary, ecosystem with life) are secondary succession as they occur in areas with existing soil and life.

Answer:

the formation of Surtsey, a volcanic island off of the southern coast of Iceland