Answer:
Natural sources include decomposition, ocean release and respiration. Human sources come from activities like cement production, deforestation as well as the burning of fossil fuels like coal, oil and natural gas.
Explanation:
Answer:
Hello There!!
Explanation:
The temperature stays the same when a solid is melting or a liquid is boiling (changing state) during a change of state, even though heat energy is being absorbed.
hope this helps,have a great day!!
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D will because water just turns from liquid to a gas by adding heat. That is a physical change. The other equations are chemical changes.
<span> the atmosphere holds about 21 per cent oxygen. Over the Earth’s 4.6 billion year history, oxygen did not appear in the atmosphere until perhaps about 2.5 billion years ago. Since then, oxygen levels have fluctuated in tandem with global geological and biological events, such as mass extinctions.</span>
