<span>The law of conservation of energy states that energy can change from one form into another, but it cannot be created or destroyed. Or the general definition is: The totalenergy of an isolated system remains constant over time. ... A device that demonstrates the Law of Conservation of Mechanical Energy and Momentum.</span>
Explanation:
USA IS THE DEVELOPING COUNTRY.
IT'S A VERY CLEAN PLACE.
1. sensorimotor: from 0-2 yrs old.
2. preoperational: from 2-7 yrs old.
3. concrete operational: 7-11 yrs old.
4. formal operational: 12 yrs old & up
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Supply and demand in these of substitutes in the market affect the prices because a substitute is Goods that satisfy similar need or like a desire and like increase the price of good witch increase the demand for its substitute while like antifreeze in the price of Good Will decreased demand for its substitute