Why did Mexico open its borders to American settlers in the early 1800s?

Please help! Please

In an economic downturn, what can happen in countries that depend on high taxes to fund social programs?

Apurging of emotions, specially pity and fear

Plz ! after the first battle of bull run general ivan mc dowell was removed from command of the union army he was replaced by a. general ulysses s. grant. b. general george mcclellan. c. general robert e lee. d. general george meade.