When you wrap a sandwich in plastic food wrap to protect it. you must first unroll the plastic wrap from the container and then wrap the plastic around the sandwich. In both steps. You encounter friction. In each step is friction helplul or not? Explain your answer

Scientist have use computer models to create a series of maps that show how susceptible coastal cities in island countries are to the sea rising at different levels.the map shows that a 1 meter rise would swap cities all along the us eastern seaboard. a 6-meter sea level rise with sub merge a large part of florida. thermal expansion has already raise the oceans 10 to 20 centimeters the most likely cause,directly and indirectly, for such a rise in sea level is