3. Which of the following are the main features of E . coli? They are: 1. glucose -positive 2. facultative anaerobes 3.lactose-positive 4.gram-negative bacteria

The main features of E. coli are:<br /><br />1. Glucose-positive: E. coli can utilize glucose as a source of energy and carbon.<br />2. Facultative anaerobes: E. coli can grow in both the presence and absence of oxygen.<br />3. Lactose-positive: E. coli can ferment lactose to produce acid and gas.<br />4. Gram-negative bacteria: E. coli has a thin peptidoglycan layer and an outer membrane, which classifies it as a Gram-negative bacterium.<br /><br />Therefore, all the options listed are main features of E. coli.