Prokaryotic cells ... never contain photosynthetic apparatus.
O may have a membrane bound nucleus but never organized membrane bound
organelles.
have organized organelles and a membrane bound nucleus.
lack both membrane bound organelles and membrane bound nuclei.

Based on the topographic map of mt. st. helens, what is the contour interval of the volcano about height is 2,950 m?

Most animal cell membranes have proteins that pump. ions out of the cell and potassium ions into this

Based on the observation that only male crickets produce a song, you hypothesize that a male's song is a form of communication to potential mates. you set up a simple experiment to test this hypothesis. in the laboratory, you place a male snowy tree cricket in enclosure a, which is adjacent to enclosureb. in enclosure b, you place other insects, one at a time, and observe their responses to the male's song. the enclosures are designed so that the two insects being tested cannot see or smell each other, but sound is transmitted from enclosure a to enclosureb.