Describe the conditions of Earth during the Precambrian
What will be an ideal response?
Answer: Hadean: intense volcanic activity, meteorite bombardment, precontinents in a state of constant change from internal and external forces.
Archean: gases from volcanic eruptions led to creation of a primitive atmosphere (rich in water, poor in oxygen) and the oceans. Blue-green algae, bacteria, and stromatolites were the first signs of life, organisms evolved a primitive form of photosynthesis, which later led to the development of the ozone layer.
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A comet is discovered in an elliptical orbit around the sun. Its closest distance from the sun is 1.0 AU, and measurements of its speed at this distance imply that its greatest distance from the sun is 7 AU. About how many years will pass between the comet’s approaches to the sun?
A. 8 y B. 16 y C. 22.6 y D. 64 y E. 226 y F. Other (specify)
The probes sent out of our solar system were carefully designed to hide any trace of their origin
Indicate whether the statement is true or false
A refrigerator has a coefficient of performance of 4 . If the refrigerator absorbs 30 cal of heat from the cold reservoir in each cycle, the heat expelled (in cal) into the heat reservoir is
a. 40.5 b. 37.5 c. 36.5 d. 34.5 e. 22.5
The Drake Equation seeks to estimate the number of technological civilizations in the galaxy
Indicate whether the statement is true or false