What two types of simple machines make up this compound machine? screw, lever

screw, incline plane

lever, pulley

lever, wheel and axle

How do diseases caused by bacteria and diseases caused by viruses react to antibiotics?

Acar company is testing seatbelts using crash test dummies. the company finds that when cars come to a sudden stop, the crash test dummies' bodies continue to move forward. the seat belt keeps the crash test dummies from hitting the back of the seat in front of them. why do the crash test dummies' bodies continue to move forward even though the car stopped? a. the friction opposing their bodies' movement keeps them in motion. b. the inertia of their bodies keeps them in motion. c. the forward acceleration of the car keeps them in motion. d. the gravity pulling on the car keeps them in motion.

Ascientific idea becomes valid when it is what?