The U.S. classification system is currently established under Executive Order 13292 and has three levels of classification - Confidential, Secret, and Top Secret. There is a designation of "unclassified" but by definition that means it is not "classified".
Other markings may be added to these categories. Subsets of these classifications may include: Controlled Unclassified Information (CUI) - sometimes also referred to as FOUO (for official use only) or Sensitive but Unclassified (SBU) - although use of the term SBU is supposed to be discontinued, Secret No-foreign, Secret with restrictions to certain countries, Secret-Compartmentalized, Top-Secret Special Compartmentalized Information (most TS is also SCI), Sources and Methods Intelligence (SAMI), ATOMAL (for atomic energy).
Reference maps and Thematic maps are the broad categories of maps
It is not possible to answer as there are many more than 2 categories.
CISC and RISC are the two categories that are used to classify CPU architecture. CISC is an acronym for complex instruction set computer.
The two main categories of seismic waves are body waves and surface waves. Body waves can travel through the earth's inner layers, but surface waves can only move along the surface of the Earth.
The two main categories of seismic waves are body waves and surface waves. Body waves can travel through the earth's inner layers, but surface waves can only move along the surface of the Earth.
Classified and unclassified
public and private
butter
butter
warrant and warrantless searches
bushfire and floods
verbal and performance.
physicians and technologists
Literature is divided into Prose and Poetry.
Generally they fall into two broad categories: hardware and software.
Retinopathies are divided into two broad categories: simple or nonproliferative retinopathies and proliferative retinopathies.
Reference maps and Thematic maps are the broad categories of maps