Explain why both a power source (like a battery) and a complete circuit are necessary for an electromagnet to function.

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Explanation:

A power source like a battery is therefore necessary to supply the electric current necessary for the magnet to work however, it will not work unless the circuit is closed as electricity cannot not flow in an open circuit because current needs to be able to flow from one end of a power source to the other end

answer: tributaries flow into rivers.

wetland is a biome that develops when the water gets accumulated in a land exhibiting a huge depression. these form either seasonally or permanently. the water in the wetland comes from rivers, lakes, ocean, flood, rain or other sources. the wetlands includes mangroves, marshes and peatland.

tributaries flow into the rivers develops a wetland because such water will get deposited in the depression and will restrict the original flow of tributary water. hence, water with low drainage current combines with the river water.

answer; i believe that the correct answer is (lung);