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Simora [160]
3 years ago
15

What was the oxygen crisis

Chemistry
1 answer:
salantis [7]3 years ago
8 0
The Great Oxidation Event (GOE), sometimes also called the Great Oxygenation Event, Oxygen Catastrophe, Oxygen Crisis, Oxygen Holocaust,[2] or Oxygen Revolution, was a time period when the Earth's atmosphere and the shallow ocean first experienced a rise in oxygen, approximately 2.4 billion years ago (2.4 Ga) to 2.1–2.0 Ga during the Paleoproterozoic era.[3] Geological, isotopic, and chemical evidence suggests that biologically produced molecular oxygen (dioxygen, O2) started to accumulate in Earth's atmosphere and changed Earth's atmosphere from a weakly reducing atmosphere to an oxidizing atmosphere,[4] causing many existing species on Earth to die out.[5] The cyanobacteria producing the oxygen caused the event which enabled the subsequent development of multicellular forms.
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Which best describes the effect of j.j. thompsons theory
dangina [55]
 The accepted model of the atom was changed.
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3 years ago
8. Which of the following are reasons why Index fossils are chosen for determining ages of rocks? Select all that apply .
igomit [66]

Answer:

B. Distributed over a very wide range

D. Limited life existence in geologic time.

Explanation:

Index fossils are very unique fossils that helps in determining the relative ages of rocks and biostratigraphic correlation. They are usually called guide fossils.

  • Fossils are the preserved remains of dead organisms found in rocks.
  • Index fossils are a special class of fossils with the following properties;
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4 0
3 years ago
Read 2 more answers
Which of the following situations indicates an alpha emission?
Angelina_Jolie [31]
Your answer would be C. Alpha decay involves the ejection of 2 protons and 2 neutrons from the nucleus for a total of 4 amu lost. This form of decay is most common in heavy elements.
4 0
3 years ago
A compound that would be most soluble in water would be: a. glucose b. cholesterol. c. a large protein. d. a triglyceride.
Mrrafil [7]

Answer:

a. glucose

Explanation:

5 0
3 years ago
You are trying to boil water while camping in the Colorado Rockies. The surrounding barometric pressure is 0.9 bar, and the wate
e-lub [12.9K]

Answer:

Perfectly Specified

Explanation:

Given,

Pressure = P = 0.9 atm

and the Boiling point = T

Number of phases P = 1

Number of components C = 1

According to Gibb's phase rule ,

F = C - P + 2

If

  • F = 0, the system is perfectly specified

  • F > 0, the system is under specified

  • F < 0 the system is over specified

At P = 0.9 atm, boiling point is T i.e. Fixed equal to 96.7 °C (from steam table)

P is independent variable and T is dependent variable (depends on the value of P ).

In this case only two variables are required to fix the system pressure and temperature.

In the given problem, pressure is fixed so the temperature is also fixed. There is no requirement of any other variable.

Therefore degree of freedom,

F = 0

The system is perfectly specified.

7 0
3 years ago
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