9.Which of the following are usually observed in subgingiva biofilm/plaque? a)Anaerobic Gram negative rods,bacilli and spirochetes b)Saccharolytic bacteria c) Aerobic Gram positive cocci and rods d) Facultative anaerobes c) Capnophilic bacteria

## Step 1<br />The problem is asking us to identify the types of bacteria that are typically found in subgingival biofilm/plaque. Subgingival biofilm/plaque refers to the bacterial colonies that form on the teeth, particularly below the gum line. These bacteria are known to be anaerobic, meaning they can survive in environments with little to no oxygen.<br /><br />## Step 2<br />Looking at the options, we can see that option a) lists "Anaerobic Gram negative rods, bacilli and spirochetes". These types of bacteria are known to be anaerobic and are commonly found in subgingival biofilm/plaque.<br /><br />## Step 3<br />Option b) lists "Saccharolytic bacteria". These bacteria are known to metabolize sugars, which is a common characteristic of bacteria found in subgingival biofilm/plaque.<br /><br />## Step 4<br />Option c) lists "Aerobic Gram positive cocci and rods". These bacteria are aerobic, meaning they require oxygen to survive. This is not a characteristic of bacteria found in subgingival biofilm/plaque, which are anaerobic.<br /><br />## Step 5<br />Option d) lists "Facultative anaerobes". These bacteria can survive in both aerobic and anaerobic environments. While they could potentially be found in subgingival biofilm/plaque, they are not the primary type of bacteria found there.<br /><br />## Step 6<br />Option e) lists "Capnophilic bacteria". These bacteria require high levels of carbon dioxide to survive, which is not a characteristic of bacteria found in subgingival biofilm/plaque.