Complete the following sentences that describe evidence found in the k-t boundary layer.
[shocked quartz, meteorites, iridium, soot, solidified rock "droplets", dust, chicxulub]
the presence of suggests an impact because these mineral grains form only under high-pressure conditions.
the presence of is thought to indicate that rock splashed upward by an impact was molten as it fell back down from the sky.
the unusually high abundance of in this layer suggests that this material came from the impact of an asteroid (or comet).
the presence of that there were world-wide forest fires at the time this layer formed.