HOTS Questions: The Mystery of Food | Our Wondrous World Class 5 - New NCERT PDF Download

Q1: If microbes require moisture, air, and warmth to spoil food, evaluate why drying is an effective preservation method in arid regions.
(a) It seals food from the air
(b) It increases air exposure
(c) It removes moisture, inhibiting microbial growth
(d) It adds warmth to speed spoilage
Ans: (c)
Explanation: Drying food in arid regions takes away the water that microbes need to grow and spoil things, like turning juicy fruits into dry ones that last longer.
Without moisture, those tiny germs can't multiply or make the food go bad quickly.
This method works well because air and warmth alone aren't enough for spoilage without water.

Q2: Analyse why oil is used in pickling, and how it differs from refrigeration in preventing spoilage.
(a) Oil creates an air barrier, while refrigeration slows microbial activity
(b) Oil freezes food like refrigeration
(c) Oil adds moisture for microbes
(d) Both methods heat food
Ans: (a)
Explanation: Oil in pickling covers the food like a blanket, blocking air that microbes need to grow and spoil it, keeping things fresh longer.
Refrigeration chills food to slow down those germs so they don't work as fast, but it doesn't block air the same way.
Both help preserve, but oil focuses on no air, while cold temps just make everything sluggish. 

Q3: Propose why good microbes in curd aid digestion, and their role in upset stomachs.
(a) They increase acidity
(b) They restore gut balance by competing with harmful bacteria
(c) They remove all bacteria
(d) They spoil food faster
Ans: (b)
Explanation: Good microbes in curd are like friendly helpers that live in your tummy and fight off bad germs by taking up space and food.
They break down food easier for your body to use, making digestion smoother.
Eating curd can calm things down without medicine sometimes.
That's why they restore gut balance by competing with harmful bacteria.

Q4: If cavities form from bacterial acid, evaluate the impact of poor oral hygiene on overall health.
(a) It only affects tooth aesthetics
(b) It has no broader effects
(c) It improves digestion
(d) It can lead to infections spreading to other body parts
Ans: (d)
Explanation: Poor oral hygiene lets bacteria build up in your mouth.
Turning sugars into acid that eats away at teeth, causing cavities. 
It might make you sick all over, not just with tooth pain.
Brushing and flossing keep everything healthy.

Q5: Compare the preservation benefits of salting versus sugaring for different foods.
(a) Sugaring spoils faster than salting
(b) Both draw out water but salting suits meats, sugaring fruits
(c) They are identical in effect
(d) Salting adds moisture, sugaring removes it
Ans: (b)
Explanation: Salting pulls water out of foods like meat, making it hard for microbes to grow, which keeps it from spoiling.
Sugaring does the same by drawing out moisture, but it works better on sweet things like fruits, turning them into jams.
Both methods dry out the food naturally without needing a fridge. 

Q6: Why might traditional spices like pepper preserve food, and how does this relate to historical trade?
(a) Antimicrobial properties inhibit microbes, valued in long journeys
(b) They add water content
(c) They have no preservation role
(d) They increase spoilage for flavour
Ans: (a)
Explanation: Spices like pepper have special powers that fight off microbes.
This stopped food from going bad during long trips in old times.
This adds flavour, too, but the main job is preservation.
That's why antimicrobial properties inhibit microbes, valued in long journeys.

Q7: If idli batter ferments due to microbes, analyse how this process benefits nutrition.
(a) It reduces nutrients
(b) It adds harmful bacteria
(c) It breaks down compounds, increasing digestibility and vitamins
(d) It makes food spoil faster
Ans: (c)
Explanation: Fermenting idli batter with good microbes changes the mix, breaking tough parts into easier-to-digest bits for your body.
This process adds extra vitamins like B vitamins, making the food healthier and yummier.
It's a natural way to boost nutrition without chemicals.
That's why it breaks down compounds, increasing digestibility and vitamins.

Q8: Evaluate the consequences if all microbes were eliminated from food production.
(a) Increased nutritional value
(b) Food would last forever
(c) No impact on preservation
(d) No spoilage, but loss of fermented foods like curd and bread
Ans: (d)
Explanation: Without any microbes, food wouldn't spoil as fast, but we'd miss out on tasty things like curd, bread, and cheese that need good germs to make.
These helpful microbes turn milk into yoghurt or dough into fluffy loaves.
Eliminating all would mean no fermentation, so less variety in what we eat.
That's why no spoilage but loss of fermented foods like curd and bread.

Q9: Propose why seasonal eating reduces reliance on preservation methods.
(a) It requires more refrigeration
(b) It promotes year-round canning
(c) Fresh produce needs less processing, minimising microbial risks
(d) It increases spoilage rates
Ans: (c)
Explanation: Eating seasonal foods means picking them fresh when they're ready, so they don't need much preserving, like canning or freezing, to last.
This cuts down on the chances of microbes spoiling them because you eat them quickly.
Less processing saves energy and keeps things natural.
That's why fresh produce needs less processing, minimising microbial risks.

Q10: Analyse how chewing food properly aids digestion beyond just breaking it down.
(a) It reduces saliva production
(b) It mixes food with enzymes in saliva for initial breakdown
(c) It speeds up swallowing
(d) It bypasses stomach processes
Ans: (b)
Explanation: Chewing food well mixes it with saliva that has special helpers called enzymes.
 It starts to break down starches right in your mouth.
This makes it easier for your stomach to do its job without working too hard.
It prevents tummy aches from big chunks. That's why it mixes food with enzymes in saliva for initial breakdown.

Q11: If factories use canning for preservation, compare its effectiveness to traditional drying.
(a) Canning seals and heats to kill microbes, and  drying removes moisture
(b) Canning allows air exposure, drying seals it
(c) Both fail in humid climates
(d) Drying is more sterile than canning
Ans: (a)
Explanation: Canning seals food in jars and heats it super hot to kill all microbes inside.
It keeps it safe for months without a fridge.
Drying takes away water so germs can't grow, but it might not kill everything like heat does.
Canning is great for soups and fruits, while drying suits herbs or meats. Both preserve well, but canning is more airtight.
That's why canning seals and heats to kill microbes, and drying removes moisture.

Q12: Why do cavities form, and how does diet influence their prevention?
(a) From lack of chewing, preventable by hard foods
(b) From over-brushing, preventable by less hygiene
(c) Independent of diet
(d) Bacteria feed on sugars, producing acid; low-sugar diets help
Ans: (d)
Explanation: Cavities happen when mouth bacteria eat leftover sugars from food and make acid that pokes holes in your teeth.
Eating less sugary stuff like candy helps because there's less food for those germs.
A good diet with veggies and water keeps teeth strong.
That's why bacteria feed on sugars, producing acid; low-sugar diets help prevent them.

Q13: Evaluate the role of good microbes in human health versus harmful ones in spoilage.
(a) All microbes spoil food
(b) Harmful ones benefit immunity
(c) They are indistinguishable
(d) Good ones aid digestion and fermentation, harmful ones cause decay
Ans: (d)
Explanation: Good microbes help our bodies by aiding digestion in the gut and making yummy fermented foods like yoghurt.
Harmful ones make food rot by breaking it down too fast, causing smells and sickness.
We need the good ones for health, but we fight the bad with preservation.
That's why good ones aid digestion and fermentation, while harmful ones cause decay.

Q14: Propose a home experiment to test microbial growth on different foods.
(a) Freeze everything
(b) Add oil to all samples
(c) Expose all to heat equally
(d) Compare moist versus dry storage over days
Ans: (d)
Explanation: For a fun home test, put the same food, like bread, in two spots – one moist, like a damp bag, one dry like open air – and watch over a few days.
You'll see mould grow faster in the wet one because microbes love moisture.
This shows why drying preserves food. 
That's why we compare moist versus dry storage over days to test microbial growth.

Q15: If global warming increases temperatures, predict the effects on food spoilage rates.
(a) No change without moisture
(b) Decreased as heat kills microbes
(c) Increased as warmth accelerates microbial growth
(d) Reduced due to evaporation
Ans: (c)
Explanation: Warmer temperatures from global warming speed up how fast microbes grow and spoil food, making things go bad quickly in hot places.
Heat gives them energy to multiply, especially if there's moisture around.
It could mean more food waste, too.
That's why it increases as warmth accelerates microbial growth.