Answer:
A mirror that has a reflecting surface that is recessed inward is called concave mirror
The significant figures also known as the significant digits or precision of a number written in positional notation are digits that carry meaningful contributions to its measurements
ANSWER: B
EXPLANATION: There are four natural states of matter: Solids, liquids, gases and plasma. The fifth state is the man-made Bose-Einstein condensates. In a solid, particles are packed tightly together so they don't move much.
Answer: Machines according to Wikipedia is "a mechanical structure that uses power to apply forces and control movement to perform an intended action. Machines can be driven by animals and people, by natural forces such as wind and water, and by chemical, thermal, or electrical power, and include a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement ".
A pulley is a wheel on an axle or shaft that is created to support movement, it makes carry loads easier.
A pulley is a simple type of machine, which in the above explained case makes carrying a load easier.
