Answer: Option D. -> Liver
:
D
The liver secretes bile juice that is stored in a sac-like structure called thegall bladder. From the gall bladder, it is released as and when required for digestion. The bile plays an important role in the digestion of fats.

:
Arrangement of teeth: 1 Mark each
1. The first set of teeth called as primary teeth, and are present in children. There are 20 in total and are gradually lost over time.
2. In humans, a total of 32teeth eventually form in the adult. They are called permanent teeth. Each adult jaw contains a set of four incisors,which are used for biting. They are chisel-shaped and are present in the middle of the mouth.
3. These four are covered on both sides by single canines,sharp tearing teeth, which are much longer in carnivorous animals like lions and tigers.
4. Towards the rear of the jaw is a pair of premolarsand then three larger molarson each side. The premolars and molars are flattened, ridged teeth with large surfaces adapted for grinding and powdering food.
5. During biting and chewing, a near-perfect placement of upper and lower sets of teeth is vital for efficiently processing ingested food. Misplacement may lead to pain, as well as poor processing of food.

:
Enzymes: 1 Mark each
Any 3
1)Salivary Amylase -saliva contains the enzyme salivary amylase, which acts on the starch in food and breaks it down to maltose.
2) Pancreatic Amylase -the pancreas secretes pancreatic juices, which contain the enzyme pancreatic amylase. This enzyme acts on the remaining complex carbohydratesand breaks them into simple carbohydrates.
3) Maltase - It acts on maltose and breaks it down into two glucose units.
4) Sucrase - It digests sucrose or table sugar into its constituent units of glucose and fructose.
5)Lactase - It breaks lactose or milk sugar into glucose and galactose.

Answer: Option B. -> fats     
:
B
Bile is a digestive juice which is produced by the liver. It helps in the digestion of lipids (fats) inside the small intestine.

Answer: Option C. -> salivary glands
:
C
Saliva is secreted by the salivary glands. There are three pairs of salivary glands- parotid, submaxillary (also called submandibular) and sublingual. Saliva contains an enzyme called salivary amylase that breaks down starch which is a complex molecule to give simple sugar.

Answer: Option A. -> rumen
:
A
Grazing animals have a large sac-like structure called rumen between the oesophagus and the small intestine.Here the food getspartially digested and is called cud. But later the cud returns to the mouth in small lumps and the animal chews it. This process is called rumination.

Answer: Option A. -> Pancreas
:
A
The pancreas is a glandular organ in the digestive system. It lies in the upper left part of the abdomen.Pancreatic juice is secreted by the pancreas.

Answer: Option C. -> egestion
:
C
Ingestion, digestion, absorption and egestion are the processes involved in digestion of a food material.
$\bullet$Ingestionis the consumption of food by an organism.
$\bullet$Digestion isthe process of breaking down food by mechanical and enzymatic action in the alimentary canal into substances that can be used by the body.
$\bullet$Absorption is the process by which thedigestedfoodmolecules areabsorbedin the small intestine.
$\bullet$The left over or undigested food is removed from the body through anus by theprocess of egestion.

:
Definition: 1 Mark
Examples: 1 Mark
Ruminants are hoof-legged grass-eating animals that stand on four limbs. They quickly swallow their leafy food and store it in the rumen. Later, the food returns to the mouth and the animal chews on it.
Ruminants include cows, buffaloes, sheep, giraffe, camel, deer, etc.

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Definition: 1 Mark
Movement: 1 Mark
Digestion: 3 Marks
Amoebais a microscopic single-celled organism found in pond water. Amoeba has a cell membrane, a round, dense nucleus and many small bubble-like vacuoles in its cytoplasm.
Movement:
Amoeba constantly changes its shape and position. It pushes out oneor more finger-like projections, called pseudopodia or false feet for movement and capturing food.
Digestion:
1. Amoeba feeds on some microscopic organisms. When it senses food, it pushes out pseudopodia around the food particle and engulfs it. The food gets trapped in a food vacuole.
2. Digestive juices are secreted into the food vacuole. They act on the food and break it down into simpler substances. Gradually the digested food is absorbed. The absorbed substances are used for growth, maintenance, and multiplication.
3. The undigested residue of the food is expelled outside by the vacuole. The basic process of digestion of food and release of energy is the same in all the organisms.