What causes symptoms associated with sickle-cell disease?
transgene effects
genetic drift
spontaneous mutation
pleiotropic effects
Metalloids are the smallest class of elements, containing just six members: boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te). Metalloids have some properties of metals (elements that can conduct electricity) and some properties of nonmetals (elements that cannot conduct electricity). For example, most metalloids can conduct electricity, but not as well as metals. Metalloids also tend to be shiny like metals, but brittle like nonmetals. Chemically, metalloids may behave like metals or nonmetals, depending on their number of valence electrons. You can learn more about specific metalloids by clicking on the element symbols in the periodic table at this URL: http://www. chemicool. com/ .