Science 9 · Unit 4: Maintaining life · Cambridge Lower Secondary Science Stage 9

Questions

1. 1. What is transpiration?

   • the loss of water vapour from the leaves of a plant
   • the uptake of water by the roots
   • the movement of sugars in the phloem
   • making food in the leaves
   Check

2. 2. Through which openings does water vapour leave a leaf?

   • xylem vessels
   • chloroplasts
   • stomata
   • root hairs
   Check

3. 3. Why is transpiration useful to a plant?

   • It stops the plant photosynthesising.
   • It lets the plant take in oxygen at night.
   • It makes the plant heavier.
   • It pulls water and minerals up from the roots and cools the leaves.
   Check

4. 4. Why do plants lose water faster at higher temperatures?

   • The roots push water out.
   • Cold air holds more water.
   • Water evaporates faster and water vapour diffuses out of the stomata faster.
   • The leaves get bigger.
   Check

5. 5. Which conditions would make a plant transpire fastest?

   • a cold, windy, wet day
   • a warm, windy, dry day
   • a cold, still, humid day
   • a warm, still, humid night
   Check

6. 6. Leaves are smeared with petroleum jelly, which blocks stomata. Which leaves lose the least water?

   • leaves with jelly on both surfaces
   • leaves with no jelly
   • leaves with jelly on the lower surface only
   • leaves with jelly on the upper surface only
   Check

7. 7. Why does a plant wilt when it doesn't get enough water?

   • Its cells become soft and floppy and can't support the plant.
   • Its xylem fills with air and becomes heavy.
   • Its leaves make too much food.
   • Its roots grow too long.
   Check

8. 8. What was Sofia's hypothesis?

   • Plants lose more water from their roots.
   • Plants grow faster when it is cold.
   • Plants lose more water from their leaves when the temperature increases.
   • Temperature has no effect on plants.
   Check

9. 9. Sofia covered the pot and soil of each plant with a plastic bag. Why?

   • so that only water lost from the leaves is measured
   • to keep the plant warm
   • to stop the plant growing
   • to keep insects away
   Check

10. 📖 This question is about a text that students read in the app.

    10. Which of Sofia's results is anomalous?

    • plant B on day 5, 861 g
    • plant C on day 8, 618 g
    • plant A on day 1, 863 g
    • plant B on day 1, 893 g
    Check

11. 📖 This question is about a text that students read in the app.

    11. Which plant lost the most mass?

    • plant B, at 20 °C
    • plant A, at 4 °C
    • they all lost the same
    • plant C, at 30 °C
    Check

12. 📖 This question is about a text that students read in the app.

    12. Plant A went from 863 g to 807 g over 7 days. What was the mean loss per day?

    • 8 g per day
    • 56 g per day
    • 807 g per day
    • 7 g per day
    Check

13. 📖 This question is about a text that students read in the app.

    13. Plant B went from 893 g to 761 g over 7 days. What was the mean loss per day, to one decimal place?

    • 18.9 g per day
    • 22.0 g per day
    • 132 g per day
    • 16.5 g per day
    Check

14. 📖 This question is about a text that students read in the app.

    14. Plant C went from 842 g to 618 g over 7 days. What was the mean loss per day?

    • 32 g per day
    • 28 g per day
    • 224 g per day
    • 36 g per day
    Check

15. 📖 This question is about a text that students read in the app.

    15. Do Sofia's results support her hypothesis?

    • Yes, the warmer the plant, the faster it lost mass.
    • No, the coldest plant lost the most.
    • No, all plants lost the same.
    Check