Question

which of the following is true about bone cells?
they are hollow

they are very brittle

they are slightly flexible

Explanation:

Bone tissue (not individual bone cells) can have hollow structures like osteons, but bone cells themselves are not hollow. Mature bone tissue is rigid, but the presence of collagen fibers gives bones slight flexibility, ruling out "very brittle" as an absolute truth for the cells/tissue function.

Answer:

they are slightly flexible