question

Why is it important that we have a rigid lithosphere overlying a weak asthenosphere?

answer

If we did not have the rigid lithosphere an weak asthenosphere,the earth would not have plate tectonics and would be covered entirely by water.

question

Why is the molten metallic outer core and the magnetic field important to life on earth?

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If we did not have the molten core and the magnetic field, we would be bombarded by cosmic rays that would strip away our atmosphere.

question

The Goldilocks scearino suggests that

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We are very fortunate to be in the right place in the universe and to have had the right conditions to develop ans sustain life

question

The earth formed approximately how many years ago?

answer

4,600,000,000

question

The heaviest element produced by nuclear fusion in a young star is

answer

Iron

question

Planetesimals, asteriod-size objects, form during the early history of the solar nebula due to

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Collisions of particles of ice, metal, and rocky material rotating about the protosun

question

What means the "the sun in the making"

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Sol

question

As they formed, due to their high temperatures and comparatively weak gravitational fields, which planet were unable to retain appreciable amounts of hydrogen, helium, and ammonia?

answer

Mercury and earth

question

Early earth was hot because

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A combination of collisions and radioactive decay produced heat

question

Earths core, mantle, and crust formed during the

answer

Hadean

question

Which one of the following represents the greatest expanse of geological time?

answer

Precambrian

question

The major source of free oxygen in the atmosphere is from

answer

Green plants

question

The process in which plants use light energy to synthesize food sugars from carbon dioxide is called

answer

Photosynthesis

question

Earths primitive atmosphere evolved from gases

answer

Expelled from within the earth

question

The waste gas released by plants as they synthesize food sugars from carbon dioxide and water is

answer

Oxygen

question

The great oxygen event marks the time, appx 2.5 billion years ago, when _________.

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There was significant oxygen in the atmsophere

question

The large size of insects and amphibians during the Pennsylvanian period has been suggested to be due to _______.

answer

An excess of oxygen

question

The modern oceans are a major repository are the greenhouse gas ________, which some organisms utilize to make their shells

answer

CO2

question

Banded iron formations are interbedded iron oxides and chert that formed on the sea floor between 3.5 and 2 billion years ago because

answer

Iron was using the oxygen produced by bacteria and chert wasna common ocean deposit

question

One important reason we do not know much about the geologic-history of the Precambrian is that

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Rocks did not exist during much of that time

question

Zircons found in continental rocks give evidence that continental crust was forming as long ago as

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4.4 billion years ago

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Continental crust is formed by

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Melting and differentiation of oceanic crust at subduction zones

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Antarctica became glaciated because

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It moved to a position over the south pole

question

Sea level rise can be caused by

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Fast seafloor spreading

question

Most __________ rocks are deviod of fossils, which hinders correlation of rocks

answer

Precambrian

question

The Appalachian Mountains formed as a result of

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The initial formations of pangea

question

The supercontinent of Pangea began to break up during the ___________ era

answer

Mesozoic

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The beginning of the Phanerozoic is marked by the ________

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Development of hard body parts, such as shells and bones

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During the early Paleozoic era, South America, Africa, Australlia, India, and perhaps China comprised the vast southern continent of _______

answer

Gondwanaland

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By the close of the Paleozoic, all the continents had fused into the single super continent of _______

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Pangea

question

At the start of the Triassic, most of the continent were above sea level, and sediments from that time are often red because _______

answer

They include iron oxides

question

The North American Cordillera formed as a result of ________

answer

The subduction of the Pacific basin beneath North America

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The most common Precambrian fossils are ______, layered mounds of calcium carbonate

answer

Stromatolites

question

Which tyoe of bacteria thrive in enviornments that lack free oxygen?

answer

Anaerobic

question

A major obstacle the first land planets had to overcome was ________

answer

Their lack of mobility because they needed water access

question

An important evolutionary step for reptiles was _____

answer

Lungs that could hold air reptiles

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The first fully land-based animals were ____

answer

Reptiles

question

The largest mass extinction in the Phanerozoic occurred in the ____

answer

Permian

question

What group of animals were the first to leave the ocean to become the first amphibians?

answer

Lobe-finned fish

question

Which era is sometimes called the "age of dinosaurs"?

answer

Mesozoic

question

Birds evolved from ____

answer

Archaeopteryx

question

One group of reptiles, exemplified by the fossil Archaeopteryx, led to the evolution of ____

answer

Birds

question

Mammals became the dominant land animals during the ______ era.

answer

Cenozoic

question

The dominant life forms during the Cenozoic Era were _____

answer

Mammals and angiosperms

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