IT is separated into two main categories (1) those which process information, such as computer systems, and (2) those which disseminate information, such as telecommunication systems.
Early agriculture can be separated into two main categories -- plantation farming with slaves and small free farmers.
You haven't stated any categories.
You tell me!
The two main categories are convenience goods and shopping goods; two lesser categories are specialty items and unsought goods.
Deoxyribose and Ribose
botany and zoology.
descriptive and inferential
Plasma & mass
yeah
animal and vegetable
linear and non-linear resistor
viruses and infections