Earth's Second Atmosphere The second atmosphere, which was the first to stay with the planet, formed from volcanic outgassing and comet ices. This atmosphere had lots of water vapor, carbon dioxide, nitrogen, and methane but almost no oxygen.
Answer:
None of the above
Explanation:
More than a billion years ago, for instance, the North American plate began a rifting process. A triple junction formed in the middle of the young continent, and a deep rift valley developed. Freshwater drained and collected in this rift valley, creating a lake.
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Answer:
I don't know what you want to know about this question can you make it a bit more understandable.
Explanation:
Answer:
c. Chemical weathering
Explanation:
One of the famous landmarks in New York City is "The Statue of Liberty." It was built in<em> 1886</em> as a gift to the Americans from France.
The statue is covered with<em> copper sheets</em>, thus, it used to have a brown color. However, over time, the color turned into greenish-blue. This is because<u> the copper sheets underwent chemical weathering</u>. Such process occurred as a result of the reaction of copper with Oxygen in the air and with water. It produced<em> "copper carbonate,"</em> which is<em> greenish-blue</em> in color. Such color was noticeable in<em> </em>1900<em>, </em>but it covered the entire statue in <em>1906.</em>
More than 75 percent
Explanation:
Let us carefully analyze this problem:
The half life of the rubidium isotope = 50 billion years
The half-life of a radioactive isotope is the time it takes for it to decay to half of its original amount.
Every 50years, we know that a rubidium isotope would split into half.
Initially when the isotope was formed, we would only have the parent atoms there. There wont be any daughter;
ratio of parent to daughter = 100 : 0
When the isotope decays to half; we would have equal number of parent and daughter:
ratio of parent to daughter at half life = 50 : 50
The age of the earth is about 4.6billion years;
this is;
x 100 = 9.2% of the half-life of the rubidium isotope.
At this time, we should know that only 9.2 percent of the daughter would have been formed.
The remaining parent would be 100 - 9.2 = 90.8% would still be left undecayed.
The ratio of parent to daughter = 90.8 : 9.2
This is more than 75% of the parent
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