Scientists agree that the early Earth, before 2.4 billion years ago, contained only trace quantities of oxygen and that the oceans were
full of dissolved iron, Data collected point toward oxygen poor, iron-rich conditions for 90% of Earth's history, with oxygen and
hydrogen sulfide present and found mostly to the surface layers and along the margins of the oceans, Scientist also agree that most
Life forms evolved initially in marine habitats. How did the marine environment change to help foster the evolution of so many life
forms?
A)
With the advent of photosynthesis, oxygen began to build up in the oceans.
B)
Volcanic lava added oxygen to Earth's crust and is dissolved in ocean
water
C)
Oxygen was the by-product of the chemical decomposition of early
Lithospheric rocks
Anaerobic cellular respiration of prokaryotes produced dissolved oxygen in
D)
the oceans
Submit

Answer:

C

Explanation:

The Earth takes how long to make 1 rotation as it goes around the sun?

The Japanese knotweed was originally brought to Europe for __________ purposes.
A.
medical
B.
nutritional
C.
ornamental
D.
conservational

Use the following stimulus to answer the next question
Unbalanced Sex Ratio
30
75-79
70-74
65-69
60-64
55-59
50-54
Males
Pemales
40-44
35-39
10.14
25-29
20-34
15-19
10-14
5.9
0.4
12 10 6 2 8 10 12
Percent
Som United Nations
24. The sex ratio represented in the age-sex graph above for Country X is
most likely the result of
1 point
O high infant mortality
O undercounting of females

What are 3 ways that languages can be revived?

What distinctive qualities of a country and its people does its literature reveal?​

The length of a shadow of a building is 30m The distance from the top of the building to the tip of the shadow is 38m Find the height of the building. If necessary, round your answer to the nearest tenth.

what is the importance of percent composition of water in the hydrate compound?​ (chemistry)

for all of its citizens. Canada's government guarantees free A. college educations B. housing C. childcare D. healthcare​

The images show two culturally significant locations. Jerusalem is a pilgrimage site for adherents of Islam, and Bodh Gaya is a pilgrimage site for followers of Buddhism.

Using the images shown, describe TWO differences between the cultural landscapes of these pilgrimage locations.

Which term best matches information at “B1”?
Question 19 options:

A spreading

B plumes

C boundaries

D surfaces

Deforestation would most directly result in which of the following

How do earthquake (seismic) waves allow scientists to determine the composition of Earth layers?
Question 20 options:

A The waves are blocked, showing the layers are solids.

B The waves are shortened, showing the layers are made of the same material.

C The waves are lengthened, showing that the mantle is made of water and salt.

D The waves are traveling at different speeds, some bend or refract, the shadow zone doesn't record any s waves, showing the layers have different compositions.

Which statements accurately describe the US-Soviet arms race? Check all that apply.

The tensions between the US and the USSR led to increased weapons development.
The development of nuclear weapons led to increased tensions between the US and USSR.
The increased development of nuclear weapons led to negotiations between the US and the USSR.
When the USSR joined the arms race, the US quickly decided to decrease its weapons production.
When the US exploded the hydrogen bomb, the USSR decided that it should convince the US to disarm.

What may form when magma comes to the surface?

a ridge

a fault

a trench

a volcano

Some Random Questions 4 You! - Part 4!
1) If you were to have either of the animals in the picture's which would it be?
2) Would you take it outside daily?
3) Would you keep in inside a kennel/cage?
4) If not where would you keep it? If so how would you decorate it?
5) Would you play with it often?
6) Would you rather sell it to a random guy that claims he's a Zoo Keeper for 2,800$? or keep it but have to give him 100$?
Bonus) Should I make a part 5 of this?

Please answer ASAP I need this within 15 mins PLZ

What is ehekutibo?? And what is it's function

What are two primary forces behind ocean currents.
A:variation in water depth by latitude
B:density differences in water
C:the positions of earth,the sun,and the moon
D:energy transfer from winds

EXERCISE B
Match each word with its meaning.
1. since
a. show on TV or radio
2. to spend
b. funny and/or interesting
g 3. boring
c. many kinds of different things
C .4. variety
d short advertisement on TV or radio
h 5. to love
e. because
6. program
f. CNN®, for example
7. channel
g. not interesting
a
f
b
d
8. entertaining
h. to like very much
9. commercialce
i. to use time to do something
I 10. entertainment j. something that is interesting to see or do,
like a movie, a show, or a restaurant
90
AMERICAN LANGUAGE​

The region drained by the Euphrates and Tigris Rivers is arid. True Or False​

WILL GIVE BRAINLIEST! PLEASE HELP!

"I am afraid for our factory manager because we will not be able to meet the 5 year quota set by the government."

These remarks best reflect which type of economy?


1.Communist

2.Bartering

3.Free Enterprise

4.Socialist

An atom of the element chromium has an atomic number of 24 and a mass number of 52. How many electrons are in an uncharged atom or chromium.

A farmer dug a well but did not find any water.

Which most likely explains why the farmer did not find water?

The water table is deeper than the well.
All the groundwater is flowing out of a spring.
The well is being dug between two vertical, impermeable layers.
The well is located where groundwater is stuck between impermeable layers.

I'm getting a hedgehog tomorrow! I think it's name should be Dew (It's a boy) what do you think?

This is 20 POINTS !!!!!!!! PLZ HELPP


What is the role of decomposers
in the ecosystem?
Give two examples of
decomposers.
What is a food chain? Where do
you fit in on the food chain?
What is a food web? Compare
and contrast food webs with
food chains.
How is energy transferred as it
flows through the trophic levels
in a food chain or a food web?
What happens to the energy that
is not transferred from one
trophic to the next?
How does the amount of energy
available change as you move
from one trophic level to the
next?
Approximately what percent of
the energy is transferred from
one trophic level to the next?
The following examples show
how energy is transferred from
one trophic level to the next.
10% of 5000 kcals is 500 kcals
10% of 300 kcals is 30 kcals
10% of 20 kcals is 2 kcals
Describe the pattern you see.
How can changes in one part of
a food web affect another part?

HELP PLS ! What causes the frequent migration of animals in Africa?
A. Global climate change
B. Political boundaries drawn by colonizers
C. Genocides
D. Water sources changing locations frequently

AWNSER FAST NOW

Which best describes a force?

a vector with magnitude and direction
a vector with speed and strength
a vector with direction only
a vector with strength only

(40 POINTS!!!!!) Which term refers to the increase in size of a population over a given amount of time?
A.
family size
B.
growth rate
C.
population
D.
population density

A conversation is for most likely want to do which of the following to the land pictured

What areas of the world have a higher incidence of Multiple Sclerosis? What are some of the possible reasons why this is so?