Streptomyces Are Aerobic Soil Bacteria That Produce Over Two-Thirds of Our

Streptomyces are aerobic soil bacteria that produce over two-thirds of our antibiotics of natural origin.Why might a bacterium produce antibiotics?

A) To kill competing bacteria of the same species
B) To protect itself from a host immune system
C) To kill competing bacteria of different species
D) To allow it to break down the cell walls of plants
E) To kill viruses that may try to infect it