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!

The cause of the
presented by AIDS patients the
destruction of CD4 helper
lymphocytes by the . With this
destruction the system
becomes impaired and body cannot
defend itself many diseases that
normally not develop in
immunocompetent .