In-text Questions — Digestion and Photosynthesis — Life Processes

1. 12 marksNCERT Cl-10 Science, In-text Qs after §5.2, Q1

   What are the differences between autotrophic nutrition and heterotrophic nutrition?

   Hint. One mode makes its own food from scratch; the other depends on food already made by someone else.

   Step 1 — Define autotrophic nutrition. Autotrophic organisms make their own food from simple inorganic raw materials — carbon dioxide and water — using an external energy source, sunlight (photosynthesis). Green plants and some bacteria are autotrophs.

   Step 2 — Define heterotrophic nutrition. Heterotrophic organisms cannot make their own food, so they depend on complex organic material already made by other organisms, which they then break down into simpler substances. Animals and fungi are heterotrophs.

   ✦ Answer: Autotrophic nutrition makes food internally from CO₂, water and sunlight (plants, some bacteria). Heterotrophic nutrition depends on complex food made by other organisms, broken down for use (animals, fungi).

   Where students slip. Saying heterotrophs 'don't need energy from the sun' — they do, indirectly, since the food they eat ultimately traces back to autotrophs that captured solar energy; the real difference is direct vs. indirect sourcing of food.

2. 22 marksNCERT Cl-10 Science, In-text Qs after §5.2, Q2

   Where do plants get each of the raw materials required for photosynthesis?

   Hint. There are four raw materials/inputs to track down — two from the environment, and two the plant already has or makes itself.

   Step 1 — Carbon dioxide. Taken in from the atmosphere through stomata in the leaves.

   Step 2 — Water. Absorbed from the soil by the roots, and carried up to the leaves through the xylem.

   Step 3 — Chlorophyll. Already present within the chloroplasts of leaf cells, since it's a pigment the plant makes itself rather than one taken in from outside.

   Step 4 — Sunlight. Absorbed directly from the sun by the chlorophyll in the leaves.

   ✦ Answer: CO₂ from the atmosphere (via stomata), water from the soil (via roots and xylem), chlorophyll already present in leaf chloroplasts, and sunlight absorbed by that chlorophyll.

   Where students slip. Listing chlorophyll as something 'absorbed from outside' like CO₂ or water — chlorophyll is a pigment the plant already contains within its leaf cells, not a raw material it takes in from the environment.

3. 32 marksNCERT Cl-10 Science, In-text Qs after §5.2, Q3

   What is the role of the acid in our stomach?

   Hint. The acid does two separate jobs — one about a specific enzyme, and one about anything unwanted that came in with the food.

   Step 1 — First role. The hydrochloric acid creates the acidic medium that the enzyme pepsin needs in order to digest proteins.

   Step 2 — Second role. It also kills many of the bacteria that enter the stomach along with food, since this gives the acid a defensive function too.

   ✦ Answer: Stomach acid creates the acidic conditions pepsin needs to digest proteins, and it also kills many bacteria that come in with food.

   Where students slip. Mentioning only the pepsin-activation role — the acid's defensive, germ-killing role is a separate and equally valid part of the answer.

4. 41 markNCERT Cl-10 Science, In-text Qs after §5.2, Q4

   What is the function of digestive enzymes?

   Hint. Think about the size of the molecules that go in versus the size of the molecules the body can actually absorb.

   Step 1 — State what enzymes are. Digestive enzymes are biological catalysts.

   Step 2 — State what they do. They break down large, complex food molecules (starch, proteins, fats) into smaller, simpler molecules (glucose, amino acids, fatty acids and glycerol), since only these smaller molecules are simple enough for the body to actually absorb and use.

   ✦ Answer: Digestive enzymes are biological catalysts that break complex food molecules down into simple ones the body can absorb and use for energy, growth and repair.

   Where students slip. Describing enzymes as simply 'helping digestion' without saying what they mechanically do — the specific action is breaking large molecules into smaller, absorbable ones.

5. 52 marksNCERT Cl-10 Science, In-text Qs after §5.2, Q5

   How is the small intestine designed to absorb digested food?

   Hint. Think about what shape would give the inner lining as much surface area as possible.

   Step 1 — Describe the structural feature. The inner lining of the small intestine has numerous finger-like projections called villi.

   Step 2 — Explain why this design helps. The villi greatly increase the surface area available for absorption, and being richly supplied with blood vessels, they carry the absorbed food away to every cell of the body.

   ✦ Answer: The small intestine's lining is covered in villi, finger-like projections that hugely increase surface area for absorption, and their rich blood supply carries the absorbed food to the rest of the body.

   Where students slip. Describing villi as increasing 'digestion' rather than 'absorption' — by this stage food is mostly already digested; the villi's specific job is absorbing the digested nutrients into the blood.

Solutions written by the tuition.in editorial team and checked against the NCERT Class 10 Science textbook, Reprint 2026-27 (jesc105.pdf) — five in-text question sets (21 questions total) plus one end-of-chapter Exercise (13 questions, not 20 as some older manifests claim). Unchanged by rationalisation; the chapter describes the breathing passage and the nephron's tubule in generic functional terms rather than naming every intermediate structure.. Questions are referenced from the NCERT textbook for identification.