1. explain how the atmosphere has changed to contain oxygen
- natural disasters eventually created oxygen
- life evolved to form single-celled organisms which started to photosynthesise
- oxygen was suddenly released from within the earth
- trees grew and produced oxygen
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Other questions in this quiz
2. What are the layers of the earth?
- crust, mantle, outer core, inner core
- top, middle, bottom
- crust, magma, outer core, inner core
- earth, plates, lava, core
3. what are meteorites?
- a meteorite is a solid piece of debris from a source such as an asteroid or a comet, which originates in outer space and survives its impact with the earth's surface. it is called a meteoroid before its impact, a meteorite's size can range from S-XL
- a heavy rock that comes from space
- parts of the moon
- unidentified rocks on earth
4. why have carbon levels been increasing?
- the burning of fossil fuels is adding carbon dioxide to the atmosphere faster than it can be removed. This means that the level of carbon dioxide in the atmosphere is increasing, contributing to global warming.
- there are too many people being born causing more carbon dioxide to be released into the atmosphere
- not enough trees are being grown to take in the carbon dioxide and release oxygen
- modern machinery requires carbon to function
5. what is the Miller-Urey Experiment?
- the Miller-Urey experiment is a fissure in a planet's surface from which geothermally heated water issues.
- the Miller-Urey experiment tested to see if life began in a pond or ocean as a result of the combination of chemicals from the atmosphere and some form of energy to make amino acids
- the aim was to see if substances now made by living things could be formed in the conditions thought to have existed on the early earth.
- the Miller-Urey experiment suggested that the original molecules of life formed with clay that, as it crystallizes, sticks together, is capable of bringing in more clay and thus start a mechanism for selecting materials