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6 天前 · Chemical composition of the body. Chemically, the human body consists mainly of water and of organic compounds —i.e., lipids, proteins, carbohydrates, and nucleic acids. Water is found in the extracellular fluids of the body (the blood plasma, the lymph, and the interstitial fluid) and within the cells themselves.
- The Editors of Encyclopaedia Britannica
4 天前 · human muscle system, the muscles of the human body that work the skeletal system, that are under voluntary control, and that are concerned with movement, posture, and balance. Broadly considered, human muscle—like the muscles of all vertebrates—is often divided into striated muscle (or skeletal muscle), smooth muscle, and cardiac muscle.
2024年5月16日 · A diagram of the human skeleton showing bone and cartilage. Protection of the heart, lungs, and other organs and structures in the chest creates a problem somewhat different from that of the central nervous system. These organs, the function of which involves motion, expansion, and contraction, must have a flexible and elastic protective covering.
On This Day In History: anniversaries, birthdays, major events, and time capsules. This day's facts in the arts, politics, and sciences. Millvina Dean, the last known person to have survived the sinking of the Titanic in 1912, died in Southampton, England; she was nine weeks old at the time of the disaster. ...
In World War I the Allies accepted self-determination as a peace aim. In his Fourteen Points —the essential terms for peace—U.S. Pres. Woodrow Wilson listed self-determination as an important objective for the postwar world; the result was the fragmentation of the old Austro-Hungarian and Ottoman empires and Russia’s former Baltic ...
As the head of the government of the United States, the president is arguably the most powerful government official in the world. The president is elected to a four-year term via an electoral college system. Since the Twenty-second Amendment was adopted in 1951, the American presidency has been
4 Oliver and Richard Cromwell served as lords protector of England, Scotland, and Ireland during the republican Commonwealth. 5 William and Mary, as husband and wife, reigned jointly until Mary's death in 1694. William then reigned alone until his own death in 1702. 6 George IV was regent from February 5, 1811.
