State whether the following statement is true or false:
An undefined nuclear region containing only nucleic acids is called a nucleolus.

(FALSE) The statement is False.
An undefined nuclear region containing only nucleic acids (and lacking a nuclear membrane) is known as the nucleoid,which is characteristic of prokaryotic cells.
$A$ nucleolus is a distinct,spherical,non-membrane-bound structure found within the nucleus of eukaryotic cells,primarily involved in ribosome synthesis.