Why is a change in the forams at the KT boundary significant? Group of answer choicesThey are sensitive to temperature changes, suggesting that the planet must have cooled significantlyThe depended heavily on the dinosaurs, suggesting the dinosaurs must have gone extinctThey are highly sensitive to radiation, suggesting a large meteorite must have hit the EarthThey were the base of the food chain, suggesting a massive worldwide extinction

(Q019) Which of the following was important in determining the cause of the K-Pg (Cretaceous-Paleogene) extinction?Group of answer choicesglass spheres in K-Pg boundary rocksiridium in K-Pg boundary clayshocked quarts in K-Pg boundary clayall of the possible answers are correct

If a supernova in space had caused the massive extinction associated with the KT boundary, what clue would it leave behind? Group of answer choicesIridiumPlutonium 244Shocked quartzTektites

The K-T extinction event was characterized by - among other things - a high sulfur content in the atmosphere. This originated from A. emissions of the Deccan Traps B. volatilization of the S-bearing asteroid C. volatilization of the S-bearing impacted rocks

What does the KT boundary represent? Group of answer choicesThe end of the cretaceous period the beginning of the cenozoic eraThe end of the carboniferous period and the beginning of the permianThe end of the cenozoic era and the beginning of the mesozoicThe end of the mesozoic and the beginning of the paleozoic era

The extreme drop in temperature that occurred approximately 2.5 billion years ago was BEST correlated with which of the following changes? Increase in atmospheric methane (CH4). Decrease in atmospheric nitrogen (N2). Decrease in atmospheric carbon monoxide (CO). Increase in atmospheric oxygen (O2) Decrease in atmospheric carbon dioxide (CO2).