What causes a disturbance which results in a wave? (btw, this is a fill in the answer, and its only one word: ))

force

Explanation:

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.

according to jean piaget, in what stage of cognitive development are children able to understand conservation task?

b. preoperational

just took it