Which best supports the evidence that an asteroid collision may have caused the extinction of dinosaurs?
Rare metal on earth called iridium isfound in layers where dinosaurs disappeared.
Many dinosaur skeletons are found in one particular rock layer.
Dinosaur fossil remains are found at the bottom of a body of water.
Bodies of dinosaurs are only found in craters where asteriods collided.
Rare metal on earth called iridium is found in layers where dinosaurs disappeared.
The evidence that best supports the hypothesis that an asteroid collision may have caused the extinction of dinosaurs is the presence of a rare metal called iridium found in layers where dinosaurs disappeared.
The piece of evidence that best supports the idea that an asteroid collision may have caused the extinction of dinosaurs is the presence of a rare metal called iridium found in layers where dinosaurs disappeared.
To understand why this supports the theory, we need to look at the explanation behind it. When a large asteroid collides with the Earth, it releases an immense amount of energy, causing widespread destruction. One of the significant consequences is the production of a massive dust cloud that blocks sunlight and disrupts the Earth's climate.
In the 1980s, scientists studying the Cretaceous-Paleogene (K-Pg) boundary, which marks the period when dinosaurs went extinct, discovered a global layer of sediment enriched with an unusually high amount of iridium. Iridium is relatively rare on Earth's surface but is plentiful in extraterrestrial objects like asteroids.
Since iridium is scarce in the Earth's crust but abundant in asteroids, the presence of high levels of iridium in the K-Pg boundary layer strongly suggests that a massive asteroid collided with the Earth during that time. The asteroid impact would have released significant amounts of iridium, which then settled in the sediments and became preserved in the fossil record.
The other options you mentioned are not as direct evidence for an asteroid collision causing the extinction of dinosaurs. Finding dinosaur skeletons in a particular rock layer or at the bottom of a body of water does not directly indicate an asteroid collision. Similarly, the presence of dinosaur bodies only in crater sites also does not prove an asteroid impact caused their extinction, as other factors can be responsible for the formation of craters.