Which of the following explain why mars does not have a balanced greenhouse effect? a. mars has an iron-rich core. b. most of the water is locked in a permafrost layer underground. c. plate tectonics prevents the release of carbon back into the atmosphere. d. there are no active volcanoes sending carbon dioxide back into the atmosphere. (it's not c)

Diego is trying to lift a piano to the second floor of his house. diego uses a pulley system and gives a big lift to the piano. the piano moves upward, then stops, and then it starts to fall to the ground. which list best describes the forces on the piano in the proper order? positive force → balanced force → negative force negative force → balanced force → positive force positive force → unbalanced force → negative force negative force → unbalanced force → positive force