Which statement best describes an isolated system? a )energy flow into and out of the system but matter is contained. b) energy is contained within the system and matter is exchanged. c) neither energy nor matter are exchanged with the surroundings. d) there is no energy or matter that exists inside an isolated system.

C. Neither energy nor matter are exchanged with the surroundings.

Explanation:

Isolated system is a system that is completely cut off from its surroundings.

In an isolated system, both energy and matter are said to be conserved.

It cannot release energy to its surroundings or it cannot take in energy from the surroundings. Apart from energy, even matter cannot be exchanged .

For example if there is a hot box which is insulated and some contents like hot water or milk are poured into it, the heat energy of the water/milk cannot be lost to the surroundings and also it will not take in any heat energy from the surroundings; and the actual amount of water/milk content doesn't change. Such a system is called an isolated system.

the answer is c. the lower legs are levers, and the knees are fulcrums. the ankles hold the loads.