Why do you think PCMS cool down after a while​

Phase change materials (PCM) are substances that absorb and release thermal energy during the process of melting and freezing

Explanation: when it cools it changes like ice melting

answer; /// i believe that the correct answer is( it left behind rich

the right answer is the third one: turnpikes went short distances to connect markets. turnpikes, also known as toll roads, were very important for trade and transportation (of people, goods and products) in the 19th century, coinciding with the expansion towards the west. they contributed significantly to the economic development of the united states.