Which of the following statements is true about diaphragm?

The Diaphragm This thin fibromuscular paition between thoracic and abdominal cavities is an impoant muscle of respiration.When it contracts,it increases the veical extend of thoracic cavity by paially flatenning its dome and displacingthe abdominal contents downwards.The firous,central pa of the diapgragm(central tendon)is slightly depressed by the hea and thus it has right and left domes.The right dome,suppoed by the liver,lies at slightly at a higher level(a little inferior to the nipple in the male)than the left. REF.Cunningham's manual of practical anatomy,Vol.2,PG.172