Final answer:
The arrival of Alonso Álvarez de Pineda signaled the start of European exploration of Texas.
Step-by-step explanation:
When Alonso Álvarez de Pineda sailed along the Gulf Coast in 1519, his arrival signaled the start of European exploration of Texas. This expedition was significant because it was the first documented European exploration of the area. Pineda created detailed maps of the coastline, providing valuable information for future expeditions and colonization efforts.
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