Ptolemy's model was Geocentric. This means that it put the earth at the center of the solar system, instead of the sun, with all celestial objects orbiting it. The first person to prove the validity of the heliocentric theory was Nicolaus Copernicus.
<span>Ions are another name for charged atoms. Some elements are electropositive, and some are electronegative. Electropositive elements such as metals like to give up electrons, thus taking on a positive charge. Electronegative elements such as chlorine attract electrons, so they become negative. When electropositive and electronegative atoms meet and exchange ions, they take on opposite charges. Because positive and negative charges attract, these charged atoms become attracted to one another. This attraction forms an ionic bond that keeps the ions together.</span>
This might have been the cause of not being exposed to this specific pollen during his years in Chicago. Allergic reactions can develop when the stimuli presented even when its not contagious causes the immune system to trigger and act in a defensive stance. This delayed effect may have been the cause of the sudden expression of the immune system.
During protein synthesis, amino acids in the cytoplasm are picked up by molecules of "tRNA" and are taken to the ribosome.
