Quiz 6

Question 1

Explain how sedimentary rock is formed

Answer 1

The bones and shells of ancient biomass are compressed over millions of years

Question 2

State what algae released into the atmosphere when they first started
Photosynthesis

Answer 2

Oxygen

Question 3

Aside from carbon dioxide,name 3 gases which scientists believe were present in smaller amounts in the earths early atmosphere

Answer 3

Nitrogen
Methane
Ammonia

Question 4

Name the physical process which scientists believe resulted in the formation of the earths early atmosphere

Answer 4

Volcanic activity

Question 5

Name 4 substances that are long term stores of carbon which originated as carbon dioxide in the atmosphere

Answer 5

Sedimentary rock,coal,oil and natural gas

Question 6

From the formation of the earths early atmosphere until now, state how the amount of oxygen in the atmosphere has changed overall

Answer 6

It has increased

Question 7

Explain why theories about the earths early atmosphere can be inconclusive and have developed and changed over time

Answer 7

The time scale of 4.6 billion years means evidence is limited

Question 8

Name the process through which algae remove carbon dioxide from the atmosphere

Answer 8

Phtosynthesis

Question 9

Explain how coal is formed

Answer 9

Ancient plants died and were covered in sediments

Subject to high temperature and pressure over millions of years

Question 10

From the formation of the earths early atmosphere until now,state how the amount of carbon dioxide in the atmosphere has changed overall

Answer 10

It has decreased

Question 11

Before living things existed,explain how the formation of oceans reduced the amount of carbon dioxide in the atmosphere

Answer 11

Carbon dioxide dissolved in the oceans

Carbonates were precipitated

Producing sediments and sedimentary rock

Question 11

state the word equation for photosynthesis

Answer 11

Carbon dioxide + water——> oxygen + glucose

Question 12

Approximately how long ago do scientists believe that algae started photosynthesis?

Answer 12

2.7 billion years ago

Question 13

Explain why the amount of water vapour in the earths early atmosphere decreased over time

Answer 13

Over time, the earth cooled
The water vapour condensed
And formed oceans

Question 14

Name the gas which scientists believe was the majority component of the earths early atomsphere

Answer 14

Carbon dioxide