Question

Why lysosome fuses and create phagosome

Answer 1

They are fused to perform a range of critical functions for the cell.
(1) The phagosome membrane encloses entering food and particulate matter and maintains an unbroken hydrophobic barrier between these potentially harmful substances from entering.
(2) The mature phagosome membrane encloses a highly acid environment during the process of prey killing and digestion and probably contains the mechanism for the acidification of the phagosome.
(3) These membranes protect the cytosol from digestive enzymes.