During the day, the portions of earth’s surface that receive sunlight absorb energy in the form of heat. during the night, earth’s surface radiates this energy back into space. what is the main form of radiation released by earth at night?

The main form of radiation released by Earth at night is infrared radiation.

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Infrared radiation is invisible to the human eyes, but we can feel it as heat.

The answer is c, i, iii, and iv. this is because farming and mining deal with harvesting raw materials, construction work falls under manufacturing, and piloting a plane is a service. ii is wrong because making bread is using  raw materials to produce goods, which would fall under the secondary sector, not primary.