Read data on a helpful trait spreading through a population

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Moths on one tree trunk (model data)

   moth color	moths
   dark	20
   light	30
   all moths	50

2. 1.

   Ari counts the moths on one trunk. What percent of the moths are dark?

   • 67%: 20 dark moths divided by 30 light moths
   • 40%: 20 of the 50 moths are dark
   • 20%: the count of 20, written as a percent
   • 60%: the light moths, 30 of the 50

3. Bacteria on one lab plate (model data)

   bacteria	count
   resistant	30
   not resistant	170
   all bacteria	200

4. 2.

   Bo reads the counts from one plate sample. What percent of the bacteria are resistant?

   • 15%: 30 of the 200 bacteria are resistant
   • 85%: the bacteria that are not resistant, 170 of 200
   • 30%: the count of 30, written as a percent
   • 0.15%: 30 ÷ 200 = 0.15, left as a decimal

5. Seedlings in one garden patch (model data)

   seedling color	seedlings
   purple	8
   white	17
   all seedlings	25

6. 3.

   Esme counts seedlings in one garden patch. What percent of the seedlings are purple?

   • 8%: the count of 8, written as a percent
   • 32%: 8 of the 25 seedlings are purple
   • 68%: the white seedlings, 17 of the 25
   • 47%: 8 purple seedlings divided by 17 white
7. 4.

   Jun reads the bars. What percent of the moths in generation 2 are dark?

   • 50%: the height of the generation 3 bar, not generation 2
   • 15%: the rise from the generation 1 bar to the generation 2 bar
   • 20%: the height of the generation 1 bar, not generation 2
   • 35%: the height of the generation 2 bar
8. 5.

   Kira compares two trunks. The bars show counts of dark moths. Which trunk has the larger share of dark moths?

   • Trunk B: it has more moths in total, so dark moths are a larger share
   • Trunk B: its bar is taller, so dark moths are a larger share there
   • Neither trunk: a chart of counts cannot show which share is larger
   • Trunk A: 18 of 40 is 45%, and 24 of 80 is 30%
9. 6.

   Luz reads the light-moth bars. The two colors make up 100% of each generation. What percent of generation 3 is dark?

   • 20%: 100% minus the generation 1 light bar of 80%
   • 150%: 100% plus the light bar of 50%
   • 50%: 100% minus the generation 3 light bar of 50%
   • 65%: the light bar of generation 2, not generation 3

10. Dark moths per 100 moths (model data)

    generation	dark moths per 100
    generation 1	20
    generation 2	35

11. 7.

    Milo reads the table. By how many percent points did the dark share rise from generation 1 to generation 2?

    • 15 percent points: 35 − 20
    • 35 percent points: the share in generation 2
    • 55 percent points: 20 + 35
    • 75%: the 15 points are 75% of the 20 you started with

12. Resistant bacteria per 100 bacteria (model data)

    round	resistant per 100
    round 1	10
    round 2	40

13. 8.

    Noah reads the table. By how many percent points did the resistant share rise from round 1 to round 2?

    • 50 percent points: 40 + 10
    • 300%: the 30 points are 300% of the 10 you started with
    • 4 percent points: 40 ÷ 10
    • 30 percent points: 40 − 10

14. Light moths per 100 moths (model data)

    generation	light moths per 100
    generation 1	70
    generation 2	45

15. 9.

    Pia reads the table. By how many percent points did the light share fall from generation 1 to generation 2?

    • 36%: the 25 points are about 36% of the 70 you started with
    • 25 percent points: 70 − 45
    • 115 percent points: 70 + 45
    • 45 percent points: the share in generation 2
16. 10.

    Zee reads the bars. What do the bars show?

    • Purple plants rose because the garden needed more of them over time
    • The share of purple plants rose across generations; a plant's own color stays the same
    • The flowers of purple plants turned a deeper purple in each generation
    • Each white plant turned purple, 20 more in 100 each generation