Final answer:
Many Americans came to Texas in the 1820s primarily for the acquisition of agricultural land and to expand the cotton kingdom through slavery.
Step-by-step explanation:
The primary reason many Americans came to Texas in the 1820s was for the acquisition of agricultural land. The Mexican province of Texas offered plentiful land at affordable prices, attracting settlers who wanted to start anew. Additionally, many Americans were slave owners and saw Texas as an opportunity to expand the cotton kingdom and practice slavery.