--- title: Browning apples, rotting and mould — how Mova does on the tests · Chemistry description: Lesson 23 of the chemistry course of Mova's primary school: 3 of 11 tests right, exam 1 of 4, every question with the options, the student's choice, the right answer and why it chose. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/school-run/chemistry/23-browning-apples-rotting-and-mould/) [home](https://md.mova.elamur.ai/free/en/) / [at school](https://md.mova.elamur.ai/free/en/school-run/) / [Chemistry](https://md.mova.elamur.ai/free/en/school-run/chemistry/) / 23 # Browning apples, rotting and mould **Tests:** 3 of 11 right · **Exam:** 1 of 4 right · **Kind:** ★ · **Understood:** 9 of 15 · **Run:** 2026-10-18, commit `f3c23ea72` Lesson 23 of the chemistry course of Mova's primary school, as Mova's small model took its tests: it had read this lesson and the ones before it and learned from their exercises. Each test shows the options in the order the student saw them, its choice, the right answer, the score of every option and why it chose. The lesson itself, sentence by sentence with trees and pragmatics: [the lesson in the corpora](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/). Every question of this lesson and each of its options parsed by Mova, with trees and pragmatics: [the lesson's questions in the corpora](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/). ### Test 1 · ★ · wrong ✗ {#t1} Josh cuts apple slices for a picnic and squeezes lemon on them. His mate laughs. Who's right? - **1.** Neither: apples never go brown — no support - **2.** Josh: the acid slows the browning — **✓ the right answer** · no support - **3.** The mate: lemon makes them rot — **← Mova's choice** · score 1 - **4.** The mate: lemon makes them browner — score 1 **Why:** It took the question to ask which statement is true. It chose option 3 with score 1, tied with another option at 1 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 17, line 10: «Tea's colour substances change in acid: lemon makes tea paler, and baking soda makes it darker.», reached through the option's own match among the sentences about the question's things. What matched: the same action «make» (+1); the same doer «lemon» (+1). Against it: a different thing acted on (counts against) (-1). The right option, 2, found no support in what it remembers. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/t1/) ### Test 2 · ★ · wrong ✗ {#t2} "bread's got a green spot, I'll just pick it off and eat the rest". Is that a good idea for soft food? - **1.** Yes, green mould is always safe — **← Mova's choice** · no support - **2.** Yes, mould is only on the surface — no support - **3.** No, mould threads can go deep inside — **✓ the right answer** · no support - **4.** No, because bread can never be eaten — no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/t2/) ### Test 3 · ★ · right ✓ {#t3} Mum wants the hard green avocado to ripen faster. What could she do? - **1.** Soak it in salty water — no support - **2.** Keep it in a dark cupboard alone — no support - **3.** Put it in the freezer overnight to soften it — no support - **4.** Put it in a bag with a ripe banana — **← Mova's choice** · **✓ the right answer** · score 2 **Why:** It took the question to ask what is done. It chose option 4 with score 2, the only option with support. Its support: lesson 23, line 7: «As a banana ripens, starch turns into sugar and the skin browns; ripening is controlled by a gas called ethylene that fruit gives off, so fruit in a bowl ripen…», reached through the same lesson line as the sentence the question matched. What matched: the same place «bag» (+2); the same circumstance (+2). Against it: a different action (counts against) (-1); a different thing acted on (counts against) (-1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/t3/) ### Test 4 · ★ · wrong ✗ {#t4} A yoghurt is two days past "use by" and the biscuits are a month past "best before". Which should you be more careful with? - **1.** The biscuits — **← Mova's choice** · no support - **2.** The yoghurt — **✓ the right answer** · no support - **3.** Both must be eaten at once — no support - **4.** Both are equally fine — no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/t4/) ### Test 5 · ★ · wrong ✗ {#t5} If you left a bowl of grapes and a box of raisins on the table for a month, what would you expect? - **1.** The raisins would rot first — **← Mova's choice** · no support - **2.** Both would rot at the same speed — no support - **3.** The grapes would rot, the raisins would keep — **✓ the right answer** · no support - **4.** Both would stay perfectly fresh — no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/t5/) ### Test 6 · ★ · wrong ✗ {#t6} "frozen chicken's been in the freezer ages so the germs are all dead, right?" - **1.** Yes, but only after a year — **← Mova's choice** · no support - **2.** Yes, freezing kills every germ — no support - **3.** No, freezing makes germs grow faster and faster in the cold — no support - **4.** No, freezing mostly stops germs but doesn't kill them — **✓ the right answer** · no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/t6/) ### Test 7 · ★ · right ✓ {#t7} On a frosty morning, Grandpa's compost heap is steaming. Ella thinks it's on fire. What's true? - **1.** Someone poured a kettle of hot water over it — score 1 - **2.** Microbes breaking down the scraps make heat — **← Mova's choice** · **✓ the right answer** · score 4 - **3.** The frost is boiling away — no support - **4.** It is on fire and needs water — no support **Why:** It took the question to ask which statement is true. It chose option 2 with score 4, against 1 for the next best. Its support: lesson 23, line 4: «Rotting is not only bad news. In a compost heap, microbes break down peelings and leaves and give out so much heat that a big heap can steam on a frosty mornin…», reached through the same lesson line as the sentence the question matched. What matched: the same action «break down» (+3); the same doer «microbes» (+2). Against it: a different thing acted on (counts against) (-1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/t7/) ### Test 8 · ★ · wrong ✗ {#t8} A pirate game says sailors kept meat fresh for months in barrels of sugar water. What did they really use? - **1.** Sugar water — **← Mova's choice** · score 9 - **2.** Ice from home — no support - **3.** Salt — **✓ the right answer** · no support - **4.** Fresh river water — score 9 **Why:** It took the question to ask what it is done to. It chose option 1 with score 9, tied with another option at 9 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 23, line 3: «Germs need water and warmth. So people keep food by taking those away: the fridge slows them, drying makes raisins, lots of sugar makes jam, and salt kept fish…», reached through the same lesson line as the sentence the question matched. What matched: it fills the role the question asks for (+5); the same thing acted on «water» (+4). The right option, 3, found no support in what it remembers. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/t8/) ### Test 9 · ★ · right ✓ {#t9} Why might a banana go brown faster in the fruit bowl next to other ripe fruit? - **1.** The bowl keeps the banana too cold — no support - **2.** Ripe fruit gives off ethylene gas — **← Mova's choice** · **✓ the right answer** · score 3 - **3.** Other fruit pushes the banana's skin — no support - **4.** Bananas hate being near apples — no support **Why:** It took the question to ask why something happens (its cause). It chose option 2 with score 3, the only option with support. Its support: lesson 23, line 7: «As a banana ripens, starch turns into sugar and the skin browns; ripening is controlled by a gas called ethylene that fruit gives off, so fruit in a bowl ripen…», reached through the same lesson line as the sentence the question matched. What matched: the same action «give off» (+2); the same doer «fruit» (+2). Against it: a different thing acted on (counts against) (-1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/t9/) ### Test 10 · ★ · wrong ✗ {#t10} "opened the jam months ago, it's still fine coz jam lasts forever" - **1.** Jam truly never goes off once it's made — **← Mova's choice** · score 3 - **2.** Opened jam still goes mouldy eventually — **✓ the right answer** · no support - **3.** Only strawberry jam goes off — no support - **4.** Jam turns into honey over time — no support **Why:** It took the question to ask which statement is true. It chose option 1 with score 3, the only option with support. Its support: lesson 23, line 3: «Germs need water and warmth. So people keep food by taking those away: the fridge slows them, drying makes raisins, lots of sugar makes jam, and salt kept fish…», reached through the option's own match among the sentences about the question's things. What matched: the same thing acted on «jam» (+2); the same action «make» (+1). The right option, 2, found no support in what it remembers. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/t10/) ### Test 11 · ★ · wrong ✗ {#t11} If you threw half a dried apricot and half a fresh apricot into a warm damp cupboard, which would grow mould first? - **1.** Neither, apricots never grow mould — **← Mova's choice** · no support - **2.** The fresh one, it has more water — **✓ the right answer** · no support - **3.** Both at exactly the same time — no support - **4.** The dried one, it has more sugar — no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/t11/) ### Exam question 1 · formal language · right ✓ {#e1} Identify the principal reason for which a cut apple turns brown upon exposure to air. - **1.** It absorbs dust and pollutants from the atmosphere — no support - **2.** Mould spores colonise it within minutes — no support - **3.** Its chemicals react with oxygen, assisted by an enzyme — **← Mova's choice** · **✓ the right answer** · score 8 - **4.** Light causes the flesh to burn — no support **Why:** It took the question to ask which statement is true. It chose option 3 with score 8, the only option with support. Its support: lesson 23, line 5: «A cut apple goes brown because air reaches its chemicals and an enzyme helps them react with oxygen; lemon juice slows this because its acid stops the enzyme w…», reached through the same lesson line as the sentence the question matched. What matched: the same action «react» (+3); the same circumstance (+3); the same doer «chemicals» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/e1/) ### Exam question 2 · formal language · wrong ✗ {#e2} It is given that a foodstuff bears the label "use by". Select the statement most accurately characterising that label. - **1.** It pertains solely to flavour and appearance — **← Mova's choice** · no support - **2.** It is of no consequence for perishable goods — no support - **3.** It pertains to safety, and the food may be unsafe thereafter — **✓ the right answer** · no support - **4.** It pertains to the date of manufacture — no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/e2/) ### Exam question 3 · formal language · wrong ✗ {#e3} Which of the following statements most accurately characterises the effect of freezing upon germs in meat? - **1.** Growth is almost halted, but most germs are not killed — **✓ the right answer** · score 1 - **2.** Germs multiply more rapidly at low temperature — **← Mova's choice** · score 4 - **3.** All germs are destroyed instantaneously — no support - **4.** Freezing renders meat safe without cooking — no support **Why:** It took the question to ask who or what does it. It chose option 2 with score 4, against 1 for the next best. Its support: lesson 15, line 8: «Most germs cannot grow in acid, so pickles keep for months in vinegar.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+4); the same doer «most germs» (+2). Against it: a different action (counts against) (-2). The right option, 1, scored 1. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/e3/) ### Exam question 4 · formal language · wrong ✗ {#e4} Ascertain the principle by which salt, sugar and drying preserve food. - **1.** They raise the temperature of the food — no support - **2.** They supply oxygen that destroys germs — no support - **3.** They deprive germs of the water they require — **✓ the right answer** · score 2 - **4.** They convert the food into a mineral — **← Mova's choice** · score 6 **Why:** It took the question to ask which statement is true. It chose option 4 with score 6, against 2 for the next best. Its support: lesson 22, line 12: «Lactose intolerance means the body cannot digest milk sugar well, because some people stop making the enzyme that breaks it down (an enzyme is a helper substan…», reached through the remembered sentence the question matched. What matched: the same thing acted on «food» (+5); the same doer «helper substance» (+3). Against it: a different action (counts against) (-2). The right option, 3, scored 2. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/chemistry/23-browning-apples-rotting-and-mould/e4/) - ← previous: [22. Milk, cheese and yoghurt](https://md.mova.elamur.ai/free/en/school-run/chemistry/22-milk-cheese-and-yoghurt/) - next →: [24. Soap and why washing works](https://md.mova.elamur.ai/free/en/school-run/chemistry/24-soap-and-why-washing-works/) - ↑ back to [Chemistry](https://md.mova.elamur.ai/free/en/school-run/chemistry/)