CBSE Questions for Class 7 Biology Nutrition In Animals Quiz 6 - MCQExams.com

• Incisors are the most anterior teeth. 
• Canines - all mammals have a single canine in each quadrant. 
• The premolars lie immediately posterior to the canines. 
• In the upper jaw, they are found in the maxillary. 
• The most posterior teeth in the jaws of most mammals are molars. 
• Humans have two incisors, one canine, two premolars, and three molars, I2 C1 P2 M3, in each quadrant of their upper jaws. 
• The numbers for each quadrant of the lower jaw are the same, and the general formula is written I2/2 C1/1 P2/2 M3/3. 

$$\textbf{Correct answer: B}$$ 

$$\textbf{Option (A):}$$ 

$$\bullet$$ Ruminant animals can not chew food when they eat, not because of their taste. It is because of the nature of the grass that they are eating. 

$$\textbf{Option (B):}$$ 

$$\bullet$$ The grass is rich in cellulose which is not able to be easily digested. This is why ruminant animals chew the cud that they ate previously.

$$\bullet$$ Cud is the fermented food which they chew because it is easier for them to regurgitate and chew. 

$$\bullet$$ It helps them digest the cellulose with the help of the enzyme cellulase in the ruminant stomach. 

$$\textbf{Option (C):}$$ 

$$\bullet$$ The hard structure of the grass is because of the presence of cellulose.

$$\bullet$$ This structure does not let ruminant animals digest food easily. But this is not the reason behind chewing the food later.

$$\textbf{Option (D):}$$ 

$$\bullet$$ Ruminant animals eat the grass as much as they need. It is not the reason behind regurgitating and chewing.

Hence, the correct answer is option (B).

$$\textbf{Correct answer: B}$$ 

$$\textbf{Option (A):}$$ 

$$\bullet$$ Incisors are present at the front of each jaw. The main function of these teeth is to cut the food. 

$$\textbf{Option (B):}$$ 

$$\bullet$$ The teeth which are present at the end of the buccal cavity or at the end of each jaw are the molars. 

$$\bullet$$ They have a flat surface which makes them easier to chew and grind food. 

$$\textbf{Option (C):}$$ 

$$\bullet$$ Canines are present on the two sides of each jaw. The main function is to tear the food. It is the longest tooth with sharp ends.

$$\textbf{Option (D):}$$ 

$$\bullet$$ Premolars are present on the two sides of the jaw and they also help in grinding and chewing food.

$$\bullet$$ But premolars are not present at the end of the buccal cavity and help with chewing.

Hence, the correct answer is option (B).

$$\textbf{Correct answer: C}$$ 

$$\textbf{Option (A):}$$ 

$$\bullet$$ Grass is formed out of carbohydrates which is why it contains amino acids but it is not rich in this product.

$$\textbf{Option (B):}$$ 

$$\bullet$$ Grass is also not reaching fatty acids as fatty acids are mainly found in fat-containing diets like butter and other milk products.

$$\textbf{Option (C):}$$ 

$$\bullet$$ Glass is rich in cellulose which is why it is one of the chief components in herbivores.

$$\bullet$$ The enzyme for breaking down the cellulose is present in these animals like the ruminant animals. 

$$\textbf{Option (D):}$$ 

$$\bullet$$ Pepsin is found in the gastric juice and it is not found in the grass. It does not act on the nutrient components of grass.

Hence, the correct answer is option (C).

• Incisors (8 total): The middlemost four teeth on the upper and lower jaws.
• Molars (8 total): Flat teeth in the rear of the mouth, best at grinding food
• Premolars (8 total): Teeth between the canines and molars.
• Canines (4 total): The pointed teeth just outside the incisors.

$$\textbf{Correct Option C}$$

$$\textbf{Solution}$$

$$\bullet$$ The rumen of alimentary canal present in the ruminant animals have numerous numbers of bacteria and protozoa present in them. These bacteria and protozoa help in carrying out the cellulose fermentation which further helps in the digestion of cellulose.

$$\textbf{Correct answer: D}$$ 

$$\textbf{Option (A):}$$ 

$$\bullet$$ The cattle have multiple parts of the stomach and methanogenic bacteria are not present in all of those parts.

$$\textbf{Option (B):}$$ 

$$\bullet$$ Omasum is the third part of the stomach. It is not methanogenic because the action of the methanogens needs to start before food digestion can take place.

$$\textbf{Option (D):}$$ 

$$\bullet$$ The rumen is the first part of the stomach of cattle. This is the part of ruminant animals in which the methanogenic bacteria is present. 

$$\bullet$$ It is important for the fermentation of food that reaches the rumen. It is a part of the specialized stomach that facilitates digestion.

$$\bullet$$ The cellulose is digested with the help of the enzyme cellulase in this part of the stomach. 

Hence, the correct answer is option (D).

$$\textbf{Correct Option B}$$

$$\textbf{Solution}$$

$$\bullet$$The given diagram represents the digestive system of an non ruminant herbivore.