In medicine, there are four levels of care: primary, secondary, tertiary, and quaternary. The levels of care refer to the complexity of the medical cases that healthcare providers treat and the skills ...

An industry is any economic activity which creates jobs and generates income. There are four main types of industry: primary, secondary, tertiary and quaternary. The type of industry a country ...

All industry is part of a chain that starts with primary industry: the production or extraction of raw materials, like agricultural products or mining; and secondary industry: the processing of these ...

Proteins and peptides form the cornerstone of cellular function, serving not only as essential catalysts and structural components but also as mediators of signalling and regulation in health and ...