What is the optical density of oil and water ?

Optical density of a material determines the ability of the material to reflect light. It is not the same as mass density of the medium, which determines the heaviness of the material. That is why petrol inspire of being less denser in terms of mass than water, it is optically more denser than water.

i sometimes feel that way too. i feel that i should hurt someone because they hurt me, but i wouldnt do it. that would make things so much worse i have so much experience with this stuff

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.