This document discusses three major types of businesses according to their activities: service companies, merchandising companies, and manufacturing companies. Service companies provide intangible services to customers using employees. Merchandising companies sell tangible goods, either as retailers directly to consumers or as wholesalers to retailers. Manufacturing companies buy materials and convert them into products to sell to other businesses or consumers. Each type has advantages like no inventory for services or quality control for manufacturing, and disadvantages such as inability to standardize services or high conversion costs.