Question

iridium is a substance found only in asteroids and other space objects. this graph shows the amount of iridium found in different sediment layers of earth. they are marked off into 17 sections representing time. what most likely happened in sediment layer 5? a massive volcano erupted, causing global warming and lava flow, which in turn caused mass extinction. more iridium was produced by space objects and dumped by local factories. the impact of a space object led to the deposit of a layer of sediment high in iridium. fewer impacts lead to a drop in iridium levels and a mass extinction caused by a lack of sunshine.

Explanation:

Iridium is mainly from asteroids and space - objects. A spike in iridium levels in a sediment layer suggests a space - object impact. Sediment layer 5 shows a high iridium level, indicating a space - object impact that deposited a layer rich in iridium.

Answer:

The impact of a space object led to the deposit of a layer of sediment high in iridium.