In the 19th century, biologists began
taking a closer look at
both animal and plant
tissues; perfecting
cell theory. Scientists
could readily tell that
plants were
completely made up
of cells due to their
cell wall. However,
this was not so
obvious for animal
cells, which lack a
cell wall. Many
scientists believed
that animals were
made of "globules."
Which idea is BEST supported by
this paragraph?