d . vacuole
17 . The fluid mosaic model presents the modern view of
a . a membrane ' s structure
b . chromosomes
c . aggregates of cells
d . the nucleus
18 . Which is not a principle of the cell theory ?
a . All matter consists of at least one cell .
b . Cells are the basic units of life .
c . All cells arise from preexisting cells .
d . All organisms are made of one or more cells .
19 . A cell membrane is a thin layer of lipid and
a . monosaccharides
b . protein
c . chitin
d . water
20 . Immerse a living cell in a isotonic solution , and water will tend to
a . diffuse into the cell .