Why did de Rubi choose to concentrate on protecting the land south of the border line instead of trying to extend protection to the large amount of territory Spain controlled from Texas north to the Rocky Mountains?

i am only doing this for the points.

randy pausch was a famous mathematician, writer and lecturer who is particularly famous for his last speech, given in 2007, "the las lecture", because he illustrates why one's dreams need to be pursued in a logical order if success is to be obtained, option c. at this time, pausch had been diagnosed with terminal cancer so he told the audience to follow their childhood dreams, which were possible to achieve. it has been recognized as one of the best motivational speech around the world.