A eukaryote is a cell with a nucleus and membrane-bound organelles.
O True
O False

How are extrusive rocks formed? magma gets trapped inside earth and cools to rock. volcanoes apply force to solid rocks and eject them. magma gets forced to earth’s surface and cools to rock. volcanoes trap lava inside earth, where it cools to rock.

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

Consider darwin's first writings on the theory of natural selection. an important point of darwin's essay on the principle of population, written in 1798, was a peer's observation that in nature plants and animals produce far more offspring than can survive, this observation can be attributed to a) charles lyell. b) thomas malthus. c) jean-baptiste lamarck. d) johann friedrich meckel.