The pure culture of E. coli was inoculated in the Kligler iron agar. The possible results of E. coli growth are which of the following: 1. yellow slant 2. gas bubbles in the butt 3. yellow butt 4. black dots in the butt

The correct answer is 1, 2, and 4.<br /><br />Explanation:<br /><br />1. Yellow slant: E. coli ferments glucose and lactose, producing acid that lowers the pH of the medium. The yellow color indicates acid production.<br /><br />2. Gas bubbles in the butt: E. coli produces gas as a byproduct of fermentation.<br /><br />4. Black dots in the butt: E. coli reduces sulfur compounds, forming hydrogen sulfide (H2S), which reacts with iron salts to produceitates.<br /><br />Option 3 (yellow butt) is incorrect because E. coli does not ferment lactose to acid, so the butt should remain red.