Lysozyme which is found in the lysosomes. They function at a relatively low pH and are so because if they functioned at physiological pH they would digest the cell. But in this case, they are in the lysosomes where they are safe and at a lower pH so when the vesicles open they can emit hydrogen ions and the lysozyme to digest the foreign material.
The best example that illustrates a sensitive period is
letter b, where the child tries to learn in speaking a second language because
this is considered to be a sensitive period in which is the period for a
development of new opportunities that a child could learn in which learning to
speak a second language is considered to be a sensitive period.
Hi , the answer is Robin Hooke, he named the cells , cells in 1665.