Approximately one billion oxygen molecules. that is because there are about 250 million molecules of haemoglobin in each cell, and each haemoglobin molecule binds to 4 oxygen molecules
Answer:
air is drawn into the lungs
lungs expand
the muscles between the ribs contract to move the ribs up and down
air pressure in the chest cavity decreases
the diaphragm contracts and flattens
Alfred Russel Wallace, a biologist, naturalist and anthropologist who studied life in the tropics of Indonesia came up with the same idea of natural selection as Charles Darwin and prompted Darwin to publish his Origin of Specie sooner rather than later. He also studied the geographic distribution of species and as as well he was a social activist who criticized capitalism and warned of damage to the environment from man's economic activities.
Answer:
lungs. that is why it is called respiratory system
Explanation:
Protista contains only unicellular organisms can either be heterotrophs or autotrophs.
