Final answer:
Trademarks emerged during the Bronze Age due to the expansion of trade and the need for product differentiation, as well as the establishment of standardized methods for indicating product origin.
Step-by-step explanation:
The emergence of trademarks was closely tied to the development of widespread trade in the Bronze Age. Trademarks did not emerge until then primarily due to the limited need for product differentiation. Moreover, the methods for indicating product origin were not standardized, making it difficult for trademarks to serve their purpose in identifying the source of a product. As trade networks expanded and competition increased, the importance of branding and trademarks grew. This need prompted producers to begin marking their goods to ensure recognition in the marketplace, leading to the development of what we now recognize as trademarks.