Question

why are lysosomes known as "scavangers of the cell '

Answer 1

Lysosomes serve as intracellular digestive system, so they are also known as digestive bags. They destroy any foreign material which enter the cell such as bacteria or virus. Lysosomes also remove the worn out and poorly working cellular organelles by digesting them to make way for their new replacements. Since they remove cell debris, they are also known as scavengers of the cell or cellular housekeepers or demolition squads. That's why lysosomes are also called "scavengers of the cell".

Answer 2

Because they contain enzymes which can digest its own cell