The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. The brain is located in the head, usually close to the sensory organs for senses such as vision. The brain is the most complex organ in a vertebrate's body. In a human, the cerebral cortex contains approximately 15–33 billion neurons, each connected by synapses to several thousand other neurons. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells.
Paul Erdős, in a standard greeting he would make when he was not contemplating some mathematical problem, as quoted in My Brain Is Open : The Mathematical Journeys of Paul Erdos (1998) by Bruce Schechter, p. 10
When you think about the Earth’s oceans you probably imagine stretches of deep, dark water, exotic marine life and pristine waves. You probably don’t think of vast islands of plastic waste such as the Great Pacific Garbage Patch, an expanse of rubbish which some say is bigger than the continental United States. It was feared that collections of plastic debris like this were growing in line with our increasing rates of plastic production over the past decades. However, scientists have recently discovered that these floating eyesores are mysteriously receding – and that’s actually not a good thing…
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