Which of the following is a way we believe that the early atmosphere of the Earth differed from the atmosphere we have today?
A) there was little if any free oxygen early on
B) there was no ozone layer early on
C) there was probably more carbon dioxide early on than there is today
D) all of the above
E) none of the above
In terms of numbers, the most common life-forms on Earth are
C) microscopic creatures, too small to see with our eyes
The average temperature on planet Earth is higher than you would expect just from the heating of sunlight alone. What is the explanation for this?
A) solid material hitting the Earth from space heats it up
B) carbon dioxide (and other gases) in the atmosphere cause a greenhouse effect
C) the rubbing of the continental plates warms up the Earth's surface
D) the heat given off by living things makes our planet warmer
E) we have no explanation for this higher temperature and that has scientists worried
Section 8.5: Cosmic Influences on the Evolution of Earth
The Moon is heavily cratered, but the Earth which "lives next door" is NOT. Why?
A) the magnetism of the Moon is more likely to attract metallic objects to hit it
B) all objects from space (no matter what their size) burn up in the Earth's atmosphere
C) the craters on the Moon are the result of active volcanoes; the Earth has few volcanoes compared to the Moon
D) the active geology and weather on Earth destroy traces of impacts over millions of years
E) the Earth is heavily cratered, but all the craters are under the ocean