Accounting
Anthropology
Archaeology
Art History
Banking
Biology & Life Science
Business
Business Communication
Business Development
Business Ethics
Business Law
Chemistry
Communication
Computer Science
Counseling
Criminal Law
Curriculum & Instruction
Design
Earth Science
Economic
Education
Engineering
Finance
History & Theory
Humanities
Human Resource
International Business
Investments & Securities
Journalism
Law
Management
Marketing
Medicine
Medicine & Health Science
Nursing
Philosophy
Physic
Psychology
Real Estate
Science
Social Science
Sociology
Special Education
Speech
Visual Arts
Question
How long ago did multicellular life forms appear in the fossil record?A) 4.5 billion years ago
B) 3.8 billion years ago
C) one billion years ago
D) 63 million years ago
E) 30 million years ago
Answer
This answer is hidden. It contains 1 characters.
Related questions
Q:
If the inflation theory is correct, the geometry of the universe is flat and Euclidean.
Q:
Euclidean geometry is useful for most common problems, but the geometry of space requires general relativity as well.
Q:
The critically bound universe, with omega = 1, is saddle shaped.
Q:
If the value of H is doubled, it would also double the age of the universe.
Q:
The cosmological principle is the ultimate extension of the Copernican principle to the entire universe, in that there is no center at all.
Q:
Describe the separation of the superforce and the effect it had on the universe.
Q:
Why was deuterium so critical in the primordial nucleosynthesis?
Q:
Fusion in giant stars takes us all the way to iron before a Type II supernova occurs. Why did it stop with helium in the far more energetic Big Bang?
Q:
Why do population II stars contain almost nothing but hydrogen and helium?
Q:
When dark matter was first discovered, some astronomers thought that Ωo was greater than one from the extra gravity, favoring what type of universe?
Q:
Describe the reasoning leading to the idea that the number of technological civilizations in the galaxy is equal to the average lifetime of a technological civilization.
Q:
Name each of the factors in the Drake equation.
Q:
What is meant by the idea life on Earth had an "interstellar origin"?
Q:
What do we mean by "life as we know it"?
Q:
Why does SETI concentrate on the water hole?
Q:
Compare the Copernican principle with the assumptions of mediocrity.
Q:
In the habitable zone, surface water must be at least partially ________ in phase.
Q:
Outside our Earth, the most likely places for life are the planet ________ and jovian moon ________.
Q:
Conducted in 1953, the ________ experiments were designed to show what types of complex molecules might have formed in the Earth's primitive environment.
Q:
An extraterrestrial observer would pick up the strongest radio signals when
A) the Earth was at perihelion.
B) North America was either rising or setting for the observer.
C) North America was directly in front of the observers.
D) at new or full moon.
E) Saturday Night Live is on.
Q:
Most SETI searches are done at
A) X-ray wavelengths.
B) infrared wavelengths.
C) visual wavelengths.
D) radio wavelengths.
E) gamma wavelengths.
Q:
In Drake's equation, which of the following is the closest estimate for the number of stars that are formed in the Milky Way Galaxy?
A) a star a day
B) a star a month
C) a star a year
D) a star a decade
E) a star a century
Q:
Which type of molecules, vital to our life, were found to have survived a fiery descent to Earth on meteorites?
A) amino acids
B) DNA
C) lipids
D) sugars
E) vitamins
Q:
What important molecules of life did Miller and Urey brew up?
A) RNA
B) fatty acids
C) lean acids
D) amino acids
E) antacids
Q:
Thanks to the far-flung Voyager and Pioneers, knowledge of our presence has now spread out over 30 light years.
Q:
The water hole lies between 18 and 21 cm in wavelength in the radio spectrum.
Q:
Around Sun-like stars, we have, to date, only found Jupiter-like planets.
Q:
Of the billions of possible combinations of atoms into organic molecules, only about 1500 actually occur.
Q:
Earth-like planets have been observed outside our solar system orbiting in the habitable zone.
Q:
The one term of the Drake equation whose value remains completely unknown is the average lifetime of a technological civilization.