Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!

Calcium is present in almost all cells and
has several functions.

has an important role in
muscular contraction, in the blood
process, in the structure of
tissue, in , in the motility of
the sperm cell [?] and in the
nervous transmission.