Organism, organ system, Organ, Tissue, Cell
Biosphere, organisation, ecosystem, community, population
Population, organism, organ system, tissue, cell
Biosphere, ecosystem, community, population, organism
Build several models of his tree house out of different materials, and see which model holds up best to wind, water, and ice.
The order of flow of oxygen within the human body may be described simply. Oxygen first is inhaled through the nasal cavity and then passes through the trachea, through the bronchi and into the lungs. In the lungs, the oxygen is passed into the blood stream through the alveoli and then is carried to the heart. The heart pumps this oxygenated blood throughout the body, primarily to organs and muscle cells, where it is consumed in respiration and is converted to carbon dioxide and excreted.
On the Galapagos Islands, Darwin also saw several different types of finch, a different species on each island. ... Finches that ate small nuts and seeds had beaks for cracking nuts and seeds. Darwin noticed that fruit-eating finches had parrot-like beaks, and that finches that ate insects had narrow, prying beaks.
