According to the law of conservation of mass, which of these is true. a. when a physical change occurs, some of the mass is destroyed. b. when a chemical change occurs, some of the mass is destroyed. c. when both a physical and chemical change occurs, mass is added. d. when either a physical or chemical change occurs, no mass is destroyed. i also don't know which subject this would sorry

Amoving company collects data about couches they move and displays the data in a table. the force along the ramp, the angle of the ramp, and the height the couch is raised to are shown. which statements correctly compare the work done to move the couches? check all that apply. the same amount of work is done for couches 1 and 3. the same amount of work is done for couches 2 and 3. the work for couch 1 is greater than the work for couch 2. the work for couch 2 is less than the work for couch 3. the work for couch 3 is greater than the work for couch 1. the work for couch 2 is greater than the work for couch 1.