As altitude increases, the available amount of oxygen to sustain mental and physical alertness decreases with the overall air pressure, though the relative percentage of oxygen in air, at about 21%, remains practically unchanged up to 21,000 metres (70,000 ft).
  State legislators in Texas (both representatives and senators) make a salary of $7,200 per year.
Senators. The salaries of senators are identical those of members of the House of Representatives. The last year in which senators and members of the House of Representatives did not have the same salary was 1991, when members of the House earned $125,100 per year and senators made $101,900.embers of the United States House of Representative earned an annual salary of $174,000 in 2009 and 2010.