Exam 23: Life

If the entire history of the Earth were scaled to fit into one day,what time of day would microorganisms first form,oxygen start becoming a significant component of the atmosphere,and humans split off from their genetic ancestors?

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Question 1

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The Earth is 4.5 billion years old.Microbes have existed since at least 3.6 billion years ago,so in our scaled day that occurs at or 4:48 A.M.Oxygen began to fill the atmosphere 2 billion years ago,so in our scaled day that would occur at or 1 P.M.Humans evolved approximately 6 million years ago,so in our scaled day that would occur at or 11:58 P.M.

Which one of the following is NOT one of the six chemical elements commonly found in living organisms?

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Question 2

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According to the theory of evolution,chemical reactions resulting in the mutation of a molecule are a natural and inevitable occurrence.

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Question 3

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True

If you wanted to find intelligent life in the universe,what spectral types of stars would you study and why?

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Question 4

The habitable zone around a star depends most on its

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Question 5

The Drake equation estimates the number of solar systems in our galaxy today that may harbor life.

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Question 6

If the most pessimistic assumptions in the Drake equation were true,we would

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Question 7

Which one of the following is NOT one of the three categories of terrestrial life based on their DNA characteristics?

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Question 8

What determines whether or not a specific mutation is passed on to future generations?

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Question 9

Some forms of life on Earth are silicon-based.

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Question 10

If we model the history of the Earth as a single day,at what time would the first primitive forms of microorganisms appear?

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Question 11

Mutations always lead to improvements in an organism's ability to survive and reproduce.

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Question 12

Terrestrial life is composed of 20 different acids that are composed of only 4 different chemical elements.

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Question 13

Carbon forms the backbone of our DNA because

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Question 14

Where do we think life first formed on the Earth?

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Question 15

The second law of thermodynamics states that

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Question 16

Approximately 10 percent of all life on Earth has been in the form of microorganisms.

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Question 17

In 1974,astronomers sent a message toward globular cluster M13.If life exists there,and it returns our signal,we won't receive it for at least another 48,000 years.Why not?

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Question 18

Name three main dangers (one human and two astrophysical)that threaten the continued existence of human life on Earth.

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Question 19

What is SETI,what is its main objective,and how does it plan to achieve its objective?

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Question 20

Showing 1 - 20 of 40

If the entire history of the Earth were scaled to fit into one day,what time of day would microorganisms first form,oxygen start becoming a significant component of the atmosphere,and humans split off from their genetic ancestors?

Which one of the following is NOT one of the six chemical elements commonly found in living organisms?

According to the theory of evolution,chemical reactions resulting in the mutation of a molecule are a natural and inevitable occurrence.

If you wanted to find intelligent life in the universe,what spectral types of stars would you study and why?

The habitable zone around a star depends most on its

The Drake equation estimates the number of solar systems in our galaxy today that may harbor life.

If the most pessimistic assumptions in the Drake equation were true,we would

Which one of the following is NOT one of the three categories of terrestrial life based on their DNA characteristics?

What determines whether or not a specific mutation is passed on to future generations?

Some forms of life on Earth are silicon-based.

If we model the history of the Earth as a single day,at what time would the first primitive forms of microorganisms appear?

Mutations always lead to improvements in an organism's ability to survive and reproduce.

Terrestrial life is composed of 20 different acids that are composed of only 4 different chemical elements.

Carbon forms the backbone of our DNA because

Where do we think life first formed on the Earth?

The second law of thermodynamics states that

Approximately 10 percent of all life on Earth has been in the form of microorganisms.

In 1974,astronomers sent a message toward globular cluster M13.If life exists there,and it returns our signal,we won't receive it for at least another 48,000 years.Why not?

Name three main dangers (one human and two astrophysical)that threaten the continued existence of human life on Earth.

What is SETI,what is its main objective,and how does it plan to achieve its objective?

Why Learn Astronomy

Patterns in the Skymotions of Earth

Gravity and Orbitsa Celestial Ballet

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Gravity Is More Than Keplers Laws

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

A Run-Of-The-Mill G-Type Starour Sun

Star Formation and the Interstellar Medium

Stars in the Slow Lanelow-Mass Stellar Evolution

Live Fast,die Younghigh-Mass Stellar Evolution

Our Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

The Origin of Structure

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