Question
At the Cretaceous-Tertiary (K-T) boundary, nearly three quarters of all life forms died out, including nearly all large vertebrates and many tropical invertebrates, most notably, the dinosaurs. How many millions of years ago did the Cretaceous-Tertiary extinction event occur?
Responses
A about 65 million years agoabout 65 million years ago
B about 12 million years agoabout 12 million years ago
C about 150 million years agoabout 150 million years ago
D about 200 million years agoabout 200 million years ago
Question 2
About 65.5 million years ago, nearly all large vertebrates and many tropical invertebrates became extinct in what was clearly a geological, climatic and biological event with worldwide consequences. In 1979, a geologist who was studying rock layers between the Cretaceous and Paleogene periods spotted a thin layer of grey clay separating the two eras. Other scientists found this grey layer, now called the K-T boundary, all over the world, and tests showed that it contained high concentrations of iridium, an element that is rare on Earth, but common in most meteorites. Also within this layer are indications of “shocked quartz” and tiny glass-like globes called tektites that form when rock is suddenly vaporized then immediately cooled. Considering this data, what is the most plausible explanation for this extinction event?
A The K-T extinction event most likely resulted from the most recent ice age.The K-T extinction event most likely resulted from the most recent ice age.
B The K-T extinction event most likely resulted from a massive volcanic eruption.The K-T extinction event most likely resulted from a massive volcanic eruption.
C The K-T extinction event most likely resulted from an asteroid impact that caused widespread geographic and climactic changes.The K-T extinction event most likely resulted from an asteroid impact that caused widespread geographic and climactic changes.
D The K-T extinction event most likely resulted from a long drought even that slowly caused the loss of large vertebrates and proliferation of smaller species.The K-T extinction event most likely resulted from a long drought even that slowly caused the loss of large vertebrates and proliferation of smaller species.
Responses
A about 65 million years agoabout 65 million years ago
B about 12 million years agoabout 12 million years ago
C about 150 million years agoabout 150 million years ago
D about 200 million years agoabout 200 million years ago
Question 2
About 65.5 million years ago, nearly all large vertebrates and many tropical invertebrates became extinct in what was clearly a geological, climatic and biological event with worldwide consequences. In 1979, a geologist who was studying rock layers between the Cretaceous and Paleogene periods spotted a thin layer of grey clay separating the two eras. Other scientists found this grey layer, now called the K-T boundary, all over the world, and tests showed that it contained high concentrations of iridium, an element that is rare on Earth, but common in most meteorites. Also within this layer are indications of “shocked quartz” and tiny glass-like globes called tektites that form when rock is suddenly vaporized then immediately cooled. Considering this data, what is the most plausible explanation for this extinction event?
A The K-T extinction event most likely resulted from the most recent ice age.The K-T extinction event most likely resulted from the most recent ice age.
B The K-T extinction event most likely resulted from a massive volcanic eruption.The K-T extinction event most likely resulted from a massive volcanic eruption.
C The K-T extinction event most likely resulted from an asteroid impact that caused widespread geographic and climactic changes.The K-T extinction event most likely resulted from an asteroid impact that caused widespread geographic and climactic changes.
D The K-T extinction event most likely resulted from a long drought even that slowly caused the loss of large vertebrates and proliferation of smaller species.The K-T extinction event most likely resulted from a long drought even that slowly caused the loss of large vertebrates and proliferation of smaller species.
Answers
GPT-4o mini
For Question 1, the correct response is:
**A** about 65 million years ago.
For Question 2, the most plausible explanation for the K-T extinction event based on the evidence you provided is:
**C** The K-T extinction event most likely resulted from an asteroid impact that caused widespread geographic and climactic changes.
**A** about 65 million years ago.
For Question 2, the most plausible explanation for the K-T extinction event based on the evidence you provided is:
**C** The K-T extinction event most likely resulted from an asteroid impact that caused widespread geographic and climactic changes.