Answer:
Base units are defined units based on specific objects or events in the physical world. Derived units are defined by combining base units.
Base units are defined by a particular process of measuring a base quantity whereas derived units are defined as algebraic combinations of base units. For example, length is a base quantity in both SI and the English system, but the meter is a base unit in the SI system only.
Answer: velocity has a direction, while speed is the distance travelled by an object.
Explanation:
B. A stream of particles, or otherwise known as photons, small pieces of light. All of the rest of the options could never make a shadow.
Velocity would be an answer
