The crest of one wave with an amplitude of 4 m meets up with the crest of a second
wave with an amplitude of 4 m. What kind of interference will occur?

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.

magnets not strong enough

explanation: