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

Questions

1. 1. What is the main job of root hair cells?

   • to absorb water and mineral ions from the soil
   • to make food by photosynthesis
   • to carry water up the stem
   • to hold the plant upright only
   Check

2. 2. Which tubes carry water up a plant stem?

   • xylem vessels
   • phloem tubes
   • stomata
   • root hairs
   Check

3. 3. What are xylem vessels like?

   • hairs on the outside of roots
   • long, empty tubes made of dead cells
   • short living cells full of chloroplasts
   • tiny holes on the underside of leaves
   Check

4. 4. After water enters a root hair, where does it go?

   • into the phloem and down to the roots
   • straight into the flowers
   • back out into the soil
   • across the root into the xylem vessels, then up the stem to the leaves
   Check

5. 5. Zara stands celery stalks in red dye. What does the red dye show?

   • how far the water has moved up the stalk
   • how much sugar the celery makes
   • how much the celery has grown
   • how much light the celery gets
   Check

6. 6. Why did Zara put each beaker in a water bath?

   • to wash off the red dye
   • to give the celery more water
   • to make the celery grow
   • to keep the dye at a fixed temperature during the experiment
   Check

7. 7. The scientists counted the root hairs on 10 plants of variety A. How should they find the mean number per plant?

   • Add up the hairs on all 10 plants and divide by 2.
   • Count the hairs on the biggest plant only.
   • Add up the root hairs on all 10 plants and divide by 10.
   • Take the middle value without adding.
   Check

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

   8. Which variety has more root hairs per plant?

   • variety A
   • variety B
   Check

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

   9. Variety A took up more water in one hour than variety B. Why?

   • It has more, longer root hairs, so a bigger surface area for absorbing water.
   • It has fewer, shorter root hairs.
   • Its leaves are bigger.
   • It was given more water.
   Check

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

    10. Which of Zara's results is anomalous?

    • 3.2 cm at 50 °C
    • 8.1 cm at 70 °C
    • 1.0 cm at 0 °C
    • 4.8 cm at 40 °C
    Check

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

    11. What should Zara do with the anomalous result when she draws her line of best fit?

    • Use it instead of all the other results.
    • Change it to match the others.
    • Make the line pass through it.
    • Leave it out.
    Check

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

    12. What conclusion can Zara make from the celery experiment?

    • As temperature increases, the rate of transport of water in celery stalks increases.
    • Plants need more water when the temperature is higher.
    • Celery leaves use water for photosynthesis.
    Check

13. 13. Why did the scientists measure the volume of water taken up per gram of wheat plant?

    • The plants were different sizes, so per gram makes a fair comparison.
    • It made the numbers bigger.
    • Grams are easier to measure than volumes.
    • Wheat plants all have the same mass.
    Check

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

    14. Which wheat variety took up the most water after 2 weeks?

    • B
    • A
    • C
    • they were all the same
    Check

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

    15. How are the results after 6 weeks different from those after 2 weeks?

    • The order stayed exactly the same.
    • All varieties took up less water.
    • Only B changed.
    • All varieties took up more water, and C overtook A to take up the most.
    Check

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

    16. Which wheat variety would be the best choice for a farmer in a very cold country?

    • C
    • A
    • B
    Check