Which choice best explains the definition of a variable? 1.A variable is one way that scientists collect and record data in a scientific investigation.

2.A variable is something that can change and may affect the outcome in a scientific investigation.

3.A variable is a type of testable question that scientists ask when beginning a scientific investigation.

4.A variable is an educated guess that scientists make before conducting a scientific investigation.

I don't have the answer but...

Explanation:

A variable is a quantity that may change within the context of a mathematical problem or experiment. Typically, we use a single letter to represent a variable. The letters x, y, and z are common generic symbols used for variables.

A variable is a quantity that may change within the context of a mathematical problem or experiment. Typically, we use a single letter to represent a variable.

it doesn't. it was imagined up in the middle ages.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west