Some bacteria are covered with a diffuse and irregular substance called what?
--a slime layer--
Either the Porifera (sponges) or the Ctenophores (comb jellies). The jury is still out on which group branched off the main animal line first.
Group 1: herbivores
Group 2: Omnivorous
Antibiotics are, initially, molecules naturally synthesized by microorganisms to fight against bacteria competing with their environment. This created a pressure of selection on the bacterial populations, leading to the appearance of resistant strains. In fact, when an antibiotic is used, only bacteria with defense systems against this molecule survive (and reproduce).
hope this helps
