When Irish<span> (poor, and Catholic) immigrants landed in the mid-19th century US they changed. They jettisoned the core of their identity – the long struggle for freedom. They joined in the oppression of African-Americans.</span>
The blank is “imaginary”.
explanation:
Two types of imaginary reference lines are used to locate positions or points and to make accurate globes and maps. These lines are called parallels of latitude and meridians of longitude.