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Freshwater does not contain any salt, salt water does however contain salt.
Answer:
Pyramid is a good representation of energy flow in an ecosystem because the shape of pyramid is wider at the bottom and pointed at the top. In the ecosystem, population of plants are maximum so it is placed at the bottom of the pyramid while the organisms such as tertiary consumers are placed at the top of the pyramid due to low in population. So pyramid is a good representation.
Answer: Fossil fuels are made up of dead plant life example trees, bushes, etc., and when burned they release carbon in the air