During the 1820s and 1830s, many people settled in Texas and California. The territories were part of Mexico. Some thought that the United States should annex those territories. The territories were soon independent of Mexico. They became part of the United States.

Which of the following is supported directly by this passage?

Mexico and the United States agreed on all national boundaries.
Mexico did not have very tight control over its northern territories in California and Texas.
Texas and California asked for U.S. military aid from Mexico.
Texas and California were only sparsely populated before the 1820s.