1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Arlecino [84]
3 years ago
15

Which describes oxygen content as Earth evolved over time? Oxygen levels sharply declined about 400 million years ago. Oxygen le

vels stay above 15 percent starting 200 million years ago Oxygen levels remain below 5 percent starting 1000 million years ago. Oxygen levels raise significantly between 1000 and 700 million years ago.
Biology
1 answer:
denis-greek [22]3 years ago
7 0

Answer:

Oxygen levels stay above 15 percent starting 200 million years ago

Explanation:

Atmospheric oxygen levels are related to the evolution on Earth and changes in geochemical cycles that involve climate variations.

The presence of O 2 and evolution of oxygen gave new opportunities to the life on Earth. Oxygen levels in atmosphere have fluctuated between 15% and 35% of atmospheric volume, since the start of the Cambrian period.

So, form the starting 200 million years ago, oxygen level stay above 15 percent and the correct option is "B".

You might be interested in
What are two techniques used to restore biodiversity
Zarrin [17]

Two techniques that are used in order to restore the biodiversity are the sawing of native seeds or planting individual plants, and the reintroduction of animal species native to the ecosystem.

The restoration of the biodiversity is practically trying to get an ecosystem in its initial, pre-destruction condition, and help it function without any human assistance after certain amount of time.

All restorations of the biodiversity are hard and take time, and there's no guarantee that the outcome will be as planned and wanted. Initially, there the sawing of native seeds and planting individual plants, which is crucial as the plants are the basis of the ecosystems. After that animal species are introduced, small and large, herbivores, omnivores, and carnivores. The people initially have to assist the functioning of the ecosystem, but the idea is to make it function properly over time on its own.

3 0
3 years ago
Read 2 more answers
Highest energy potential of the 4 organic molecules found in living things
anyanavicka [17]

carbohydrate are the largest organic molecules

8 0
3 years ago
What does it mean when light from a galaxy is redshifted? (Earth Science)
il63 [147K]
'Red shift' is a key concept for astronomers. The term can be understood literally - the wavelength of the light is stretched, so the light is seen as 'shifted' towards the red part of the spectrum.

Hope this helps.
3 0
3 years ago
Read 2 more answers
Occurs when the population is well below the carrying capacity.
Alexeev081 [22]

Answer:

A

Explanation:

4 0
3 years ago
Which of theses choices is considered an environmental cost?. A.processing expenses B.Pollution relases C.Net profit D.Product p
AURORKA [14]
The answer is B, pollution releases because it negatively affects the environment
7 0
4 years ago
Read 2 more answers
Other questions:
  • Write the molecular formula for glucose (C6H12O6)
    14·2 answers
  • PYSCHOLOGY HELP!!
    14·2 answers
  • Scientists are studying diversity of disease prevalence in golden retrievers. What type of diversity are they studying? A. Ecosy
    9·2 answers
  • A close evolutionary relationship between annelids and mollusks is suggested by the presence of a _____ larva in both phyla as w
    13·1 answer
  • Which organism is a fungus-like protist?
    15·2 answers
  • Lactase is classified as which of the following macromolecules?
    5·1 answer
  • Please Help!!!
    15·2 answers
  • Which is an example of mechanical digestion that occurs in the human digestive system?
    6·1 answer
  • What is the main function of the immune (lymphatic) system?
    5·2 answers
  • Vestigial structures-definition
    15·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!