The idea that states are unitary actors acting under anarchy and the structure of the system shapes their behavior is associated with which theory?

Neorealism

Explanation:

Neorealism is a theory of international relations that emphasizes that power is the most important tool.

It further argues that in neorealism or structural realism, the anarchic ordering principle of the international structure is decentralized, meaning there is no formal central authority; every sovereign state is formally equal in this system. These states act according to the logic of egoism, meaning states seek their own interest and will not subordinate their interest to the interests of other states.

i think its

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.