You have decided to study the effect of loud noise on plant growth. you put one plant in a quiet room and the other plant in your school's band hall. providing each plant with the same amount of water is an example of a
a. data.
b. control.
c. variable.
d. observation.

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.

the higher the current the higher the mag field around it the higher the influence on the compass

the closer the planet is to the sun, the larger the gravity