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 and representatives alike earn only $7,200 per year, or $14,400 for a two-year legislative period. Some may consider this salary generous, since after all legislators work only for 140 days over two years. However, this salary equals just slightly over $100 per day.his adds up to $17,920 for the regular 140-day session. Annual compensation for the year in which the legislature is in session totals $25,120  which includes the $7,200 salary and $17,920 per diem allowance.