The following are true about the tear film:
a. the normal volume is about 20 ul
b. its main protein content is made up of immunoglobulins
c. the lysozyme concentration is the greatest
d. the concentration of Ig A is greater than that of Ig G
a. the normal volume is about 20 ul
b. its main protein content is made up of immunoglobulins
c. the lysozyme concentration is the greatest
d. the concentration of Ig A is greater than that of Ig G