The main process for creating oxygen in the atmosphere was: A- photosynthesis by cyanobacteria B- meteorite impacts C- breakdown of water vapor by ultraviolet radiation D- outgassing during volcanic eruptions

How did Earth develop an oxygen-rich atmosphere?Question 58Select one:Photosynthesis by algae released oxygen, which accumulated gradually.The Earth was bombarded by oxygen-rich comets which also filled the oceans with water.Sunlight broke water down to form oxygen and hydrogen.The weathering of rocks released oxygen in the rock cycle.

How did Earth's atmosphere become oxygen-rich?A.Biological activityB.Volcanic outgassingC.Ozone depletionD.Tectonic movementSUBMITarrow_backPREVIOUS

Evaluate which of the following statements about the great oxygenation event are true. Cyanobacteria in the oceans produced a large amount of oxygen as the product of a chemical reactionThe proportion of carbon dioxide in the atmosphere increasedCyanobacteria in the oceans used up most of the oxygen in the atmosphere for photosynthesisBefore the event, no organisms were capable of photosynthesisTotal available marks: 5

Which gas formed a major part of the early atmosphere?Carbon dioxideNitrogenMethaneAmmonia2The early atmosphere contained a large amount of water vapour. What happened to this?It condensed to form the oceansIt evaporated into spaceIt was used by plants for photosynthesisIt was used by animals for respiration3Which process has reduced the levels of carbon dioxide in the atmosphere to the low levels we have today?Formation of sedimentary rocksAll of theseFormation of fossil fuelsPhotosynthesis4The levels of methane and ammonia in the early atmosphere decreased over time, while the level of nitrogen increased. What is the best explanation for this?Human activities such as burning of fossil fuels and farmingMethane and ammonia are unreactive, while nitrogen reacts with oxygenMethane and ammonia react with oxygen, while nitrogen is unreactivePlants absorb methane and ammonia, and they produce nitrogen5Which two gases together form approximately 99% of the modern atmosphere?Nitrogen and oxygenNitrogen and hydrogenOxygen and hydrogenOxygen and carbon dioxide6Approximately what percentage of carbon dioxide is found in the modern atmosphere?0.9%0.004%1%0.04%

(Q008) The great oxygenation event, which added abundant oxygen to the atmosphere beginning about 2.4 Ga, was due to theGroup of answer choicesappearance of Ediacaran fauna.evolution of photosynthetic organisms in oceans.emergence of multicellular organisms.appearance of photosynthetic plants on land.