Describe and discuss mass extinctions during the Paleozoic and Mesozoic. How do these mass extinctions differ? What will be an ideal response?
There were mass extinctions of marine organisms at the end of the Ordovician and Devonian
periods. The mass extinction at the end of the Ordovician is the result of extensive glaciation
causing cooling of surface waters and lowering of sea level creating stressful conditions for
near-surface phytoplankton and shallow water marine faunas. Another extinction event
occurred at the end of the Devonian, involving major barrier reef-building organisms and
primitive armored fish. One of the most serious mass extinctions of marine organisms
occurred at the end of the Permian. During this mass extinction, 96 percent of all marine
invertebrate species were destroyed and 65 percent of land animal species. The mass
extinction between the Mesozoic and Cenozoic wiped out the dinosaurs and a smaller proportion of marine organisms.
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Discuss the composition and characteristics of Earth's layers. How was the composition of the mantle
and core determined? What will be an ideal response?
What is mean by a geostrophic current?
What will be an ideal response?
What term describes the large-scale weather phenomenon that occurs when prevailing winds in the Pacific Ocean weaken, resulting in above average warming?
A. ENSO B. greenhouse effect C. rain shadow effect D. SNSO E. heat island effect
Judge the following sentence according to the criteria given below: Different hemispheres on Earth are tilted more directly toward or away from the Sun during Earth's yearly orbit BECAUSE Earth revolves around the Sun in an elliptical orbit that
varies from a perfect circle. A) The assertion and the reason are both correct, and the reason is valid. B) The assertion and the reason are both correct, but the reason is invalid. C) The assertion is correct, but the reason is incorrect. D) The assertion is incorrect, but the reason is correct. E) Both the assertion and the reason are incorrect.