My family has some rules. Firstly, one of the most important rules in my family is that each member of my family has to be responsible for household chores. For example, my mother goes shopping and prepares the meals, my dad mends things around the house in his free time, my sister does the laundry and I usually clean the house. Secondly, we always do morning exercise every day because we want to have better health. Finally, my sister and I must be home before 10 p.m because my parents are very strict. In spite of a lot of rules, I feel comfortable and safe because I know that my parents want the best things for me.
Answer:
72 percent of the atmosphere is below the common cruising altitude of commercial airliners (about 10,000 m or 32,800 ft). 99.99999 percent of the atmosphere is below the highest flight altitude of the aircraft X-15, which reached 354,300 ft (108 km) on August 22, 1963.
