What is an energy pyramid?

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Select the situation bellow that would produce a total displacement of zero. a. a trip to the moon and then to mars b. a horse galloping from one end of a field to another c. the criss-crossing path of a bug as it flies from flower to flower d.a round-trip ride to school and back

The body of water found at number 4 on the map above is the

Can someone i have no idea of how to do this.