Huntington's disease is an incurable, progressive nerve disorder. symptoms of tbe disease generally appear between the ages 30 and 50. the allele for huntington's disease is dominant. is it possible for a child to be born to a parent with huntington's disease to not develop the disease later in life?

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

mountains can affect the climate of nearby lands. in some areas, mountains block rain, so that one side of a mountain range may be rainy and the other side may be a desert. much of airborne moisture falls as rain on the windward side of mountains.

explanation: