Final answer:
The Swahili ruler's promotion of peaceful trade with India before 1450 exemplifies how expanding trade networks were used to bolster state development along the Indian Ocean.
Step-by-step explanation:
The third paragraph of the Swahili history most directly illustrates how rulers in the Indian Ocean before 1450 used expanding trade networks to facilitate state development. Specifically, it highlights the actions of a Swahili ruler who, rather than using military might, focused on peaceful means to rule and expand his kingdom's wealth through maritime trade. By sending merchants on voyages to India, the ruler amplified his kingdom's prosperity, which in turn, reinforced the state development.