Worksheet Solutions: Digestive System - 2

Q1: Fill in the blanks

(ii) The digestive juices present in the mouth is _________.
Ans: salivary
When you chew, the food mixes with saliva. Saliva makes food soft and wet so it can be swallowed easily. It also begins to break down some parts of the food right in the mouth.

(iii) The food pipe takes the food to the _________.
Ans: stomach
After chewing, the food moves down the food pipe into the stomach. The stomach continues to break the food into smaller pieces so digestion can go on.

(iv) Digestion is completed, and food is absorbed into the blood in the __________________.
Ans: small intestine
The small intestine is where digestion finishes, and the tiny pieces of food are taken up into the blood. The blood then carries these nutrients to all parts of the body so we get energy and grow.

(v) Water is absorbed from the undigested food in the __________________.
Ans: large intestine
The large intestine soaks up water from the leftover, undigested food. This makes the waste thicker before it leaves the body. In this way, the body saves water and prepares the waste to be thrown out.

Q2: True or False.

(i) The enamel is harder than bone.
Ans: True.
Explanation: Enamel is the hardest part of the human body. It covers the outer surface of the tooth and is harder than bone, so it protects the tooth from wearing away.

(ii) Every time a tooth falls off, a new tooth grows in its place. 
Ans: False.
Explanation: Baby (milk) teeth fall out and are replaced by permanent teeth once. After permanent teeth come in, they do not grow back again if they are lost. That is why we should take care of our permanent teeth.

(iii) All teeth have the same shape. 
Ans: False.
Explanation: Teeth have different shapes for different jobs. Incisors are for cutting, canines are for tearing, and premolars and molars are for grinding food. This difference helps us eat many kinds of food.

(iv) The dentine is the softest part of a tooth.
Ans: False.
Explanation: Dentine lies under the enamel and is softer than enamel but not the softest. The softest part of a tooth is the pulp, which contains nerves and blood vessels.

(v) Once a cavity is formed in a tooth, it has to be taken out.
Ans: False.
Explanation: Small cavities can be fixed by a dentist using fillings. Only when decay is very bad, and the tooth cannot be saved, may the tooth need to be removed. Regular brushing and dental check-ups help stop cavities from getting worse.

Q3: Multiple Choice Questions (MCQs).

(i) How many teeth does a child of age 3 have?
(a) 20 milk teeth
(b) 20 permanent teeth
(c) 32 milk teeth
(d) 32 permanent teeth
Ans: (a)
Explanation: By the age of three, most children have all 20 milk (primary) teeth. These include incisors, canines and molars that help the child bite and chew soft foods.

(ii) The hardest part of teeth is the:

(a) Enamel
(b) Dentine
(c) Pulp
(d) Gum

Ans: (a)
Explanation: Enamel is the outer covering of the tooth and is the hardest substance in the body. It protects the tooth from damage and wear, while dentine and pulp are softer and lie beneath it.

(iii) Which teeth in your mouth are wide and flat?
(a)Incisors
(b) Molars
(c) Premolars
(d) Both (a) and (b)

Ans: (b)

Explanation: Molars are wide and flat. They are at the back of the mouth and have large surfaces to grind and crush food, so it is easier to swallow and digest.

(iv) You get a toothache when a cavity in the tooth reaches the:
(a) Crown
(b) Dentine
(c) Pulp
(d) Gum
Ans: (c)
Explanation: The pulp is the soft centre of the tooth that contains nerves. If decay reaches the pulp, the nerves get irritated, and you feel pain, which we call a toothache.

Q4: Give One-Word Answer.

(i) The process of breaking down food into a simpler form.
Ans: Digestion
Explanation: Digestion is how our body changes food into small, simple parts so it can use them for energy, growth and repair.

(ii) A vegetable eaten raw.
Ans: Salad
Explanation: Raw vegetables like cucumber, carrot and lettuce are often cut and mixed to make a salad, which we eat without cooking.

(iii) A food item rich in starch.
Ans: Potato
Explanation: Potatoes contain a lot of starch, which gives our body energy when we eat them.

(iv) A digestive liquid secreted by salivary glands.
Ans: Saliva
Explanation: Saliva is the watery liquid made in the mouth that helps in chewing, swallowing and starting the digestion of some foods.

(v) The diet which contains all the nutrients in the right amount.
Ans: Balanced
Explanation: A balanced diet gives the body the right amounts of different foods-fruits, vegetables, grains, proteins, and milk-to keep us healthy.

Q5: Answer the following questions.

(i) Name four organs of your digestive system which make digestive juices.
Ans: The four organs of your digestive system, which make digestive juices, are the salivary glands, the small intestine, the liver and the pancreas.

(ii) How is saliva useful in swallowing food?
Ans: Saliva mixes with chewed food and makes it soft and slippery, so it can be swallowed easily and move down the food pipe into the stomach.

(iii) What happens to the food in the small intestine?
Ans: In the small intestine, food mixes with more digestive juices and is broken into very small parts. These small food parts are then absorbed into the blood to be carried to the rest of the body.

(iv) What happens to the undigested portion of food?
Ans: Water is absorbed from the undigested food in the large intestine, and the remaining solid waste is passed out of the body through the anus.

(v) How is fibre useful?
Ans: Fibre helps to keep the bowels moving and makes it easier to remove waste from the body. It helps prevent constipation and keeps the digestive system healthy.