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
WHERE ARE THE EXPERTS AND ACE!! THIS IS MY LAST QUESTION WILL GIVE BRAINLIEST SHARE YO SMARTNESS!!
siniylev [52]

Answer: A

Explanation:

A is correct, since developed countries don't have as high birth rates, which decrease growth rate (it's actually pretty interesting when you look at the data and compare developed and non-developed countries in terms of birth rates.

B is wrong, since that would increase growth rates.

C is wrong, since (though that's true due to better medicine) that would increase growth rates.

8 0
3 years ago
Read 2 more answers
Do you think murder committed during sleep walking is a punishable offense? Why?
Pepsi [2]

Answer:

no because ur sleep walking and u cant control that

8 0
3 years ago
Read 2 more answers
What are the ways in which captive breeding helps protect biodiversity? Check all that apply.
Rudik [331]

I do not know the options, but, follow this criteria and you should be able to finish the exercise:

Usually, animals that are in captivity are endangered animals, with few individuals left. When we captivate them, the risks of them dying (either naturally or by poaching, hunting, contamination, etc) is lower, since we are taking direct care of them.



Hope it helped,


BioTeacher101

4 0
3 years ago
How do enzymes affect chemical reactions in living organisms
Arisa [49]

Answer:

Enzymes are catalysts for chemical reactions in living things. Enzymes, like other catalysts, lower the activation energy and increase the rate of chemical reac- tions. ... This means that enzymes do not change the direction of a reaction— they just change the amount of time needed for equilibrium to be reached.

Explanation:

6 0
3 years ago
Transcription factors in eukaryotes usually have DNA binding domains as well as other domains that are also specific for binding
trapecia [35]

Answer:

A) repressors

Explanation:

A transcription factor is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to specific DNA sequence. The function of TFs is to regulate-turn on and off genes-In order to make sure that they are expressed in the right cell, at the right time and in the right amount throughout the life of the cell and the organism. Groups of TFs function in a coordinated fashion to direct cell division, cell growth and cell death throughout life.

5 0
4 years ago
Other questions:
  • If each new cell made after mitosis is _______ to the original "mother" cell. This means that skin cells can replace dead, dying
    10·1 answer
  • Which human activity is most affected by increasing numbers of dead zones in the ocean
    12·1 answer
  • HELP!!<br><br> What are the steps from gene to protein? Label and describe each step.
    6·1 answer
  • True or False: Changes in an organism can't occur because of an outside force, such as a massive earthquake.
    11·2 answers
  • Modern fishing techniques use giant nets to harvest large numbers of fish in the short term. this may result in severely reduced
    5·1 answer
  • Does the ph level of acid in our stomachs affect the digestion of proteins
    12·1 answer
  • The questions are in the pic, they are about gravity :)
    5·1 answer
  • Special Class Reproduction chapter for class 9th<br><br><br><br><br><br>uxr-nvys-zwi​​
    13·1 answer
  • PLEASE HELP
    12·2 answers
  • What cell feature is responsible for storing water?
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!