a person who sees an event, typically a crime or accident, take place

to serve as a member of a council, jury, or other official body

making an effort to do something

to control or keep in check

show little or no respect for someone

is an element of a set that, taken as a whole, comprises a system of numeration

the numerical value that a digit has by virtue of its position in a number

relating to or denoting a system of numbers and arithmetic based on 10, 0.1, and powers of 10

is the ability of a solid to be dissolved into a liquid

is the manipulated variable that causes a difference or change in experiment

is the responding variable that is the effect of the manipulation in an experiment