Which of the following best summarizes the law of conservation of mass? a. matter can be changed but not created or destroyed. b. matter can be destroyed during a chemical reaction. c. matter that gains mass during a chemical reaction is evidence that matter can be created.

When a neutral charge, comes into contact with a positive charge they repel each other nothing happens the neutral charge becomes negative they attract each other

20. threshold braking in the vehicle's braking system occurs when a. the brake pedal is pushed, heel on floorboard, with full foot pressure. b. the brakes are exerting full braking power, without traction loss. c. the driver begins pushing down the brake pedal, with moderate slowdown. d. the brakes just begin to take hold with a gradual slowdown.

Matter is needed to transfer thermal energy bya. conductionb. convectionc. radiation d. both a & b.