Judge a biology claim: evidence, reasoning and reliable sources
Grade 9 Science Worksheet
Circle the best answer.
Ari's claim: "Compost helps bean plants grow taller." Which evidence supports it best?
- 20 plants with compost averaged 25 cm; 20 without averaged 17 cm, same light and water
- Compost is made from old leaves
- A gardener on a video says compost helped
- One plant given compost grew to 25 cm
Bo's claim: "Warm rooms make bread mold appear sooner." Which evidence supports it best?
- One slice left out on a warm day grew mold
- Mold is a kind of fungus
- Slices at 22 °C showed mold in 5 days on average; at 4 °C, in 12 days
- A cooking blog with no author or date says warm kitchens grow mold faster
Esme's claim: "Bees in this garden visit purple flowers more than white ones." Which evidence supports it best?
- A garden shop near the school sells more purple flower seeds than white ones
- Counts on 10 mornings: purple averaged 24 visits, white averaged 6
- One bee landed on a purple flower
- Purple is a popular color
Kira's claim: warm water helped yeast make more gas. Mean gas was 8 mL at 20 °C and 22 mL at 40 °C. Which reasoning fits?
- Warm water looks bubblier and fizzier, so the yeast must be working harder
- Yeast just prefers warm water
- The warm bottles made 22 mL of gas
- Warmth speeds up the reactions yeast uses to break down sugar
Read this first
Days until mold was first seen, 5 slices each (example data)
Where kept Temperature Mean days fridge 4 °C 12 counter 22 °C 5 Luz's claim: mold grows faster on warm bread. Which reasoning links the evidence to the claim?
- Any warm bread will grow mold, wherever it is kept in the house
- Mold is alive, and warmth speeds up the reactions in its cells
- Counter slices showed mold in 5 days
- Warm bread smells more like mold
In a survey of 6 school gardens, gardens with more bird feeders had more flowers. Milo's friend says feeders make flowers bloom. Which response is best?
- They rise together, but another factor, like care or sunlight, could explain both
- The feeders cause the blooms, since both go up
- More feeders went with fewer flowers
- The survey settles that feeders help flowers
In Pia's garden, plants given rainwater grew taller than plants given circle water. The rainwater plants were also in sunnier beds. Which conclusion is best?
- Sunlight also differed, so rainwater may not be the cause
- Rainwater is the cause, since those plants were taller
- Tap water harms any plant it touches, so gardens should skip it
- Sunlight has no effect on plant growth
Use this
Two sources (invented examples). A: a university extension page with references, last reviewed in 2025. B: a shop page selling "super seed powder", with no references.
Ren compares two sources about seed sprouting. Which is more reliable, and why?
- B, since a store that sells the powder knows its own product well
- B, since it has the most excited reviews
- Both equally, since both are online
- A, since it cites evidence and has nothing to sell
Use this
Two sources (invented examples). A: a peer-reviewed journal article that tested 200 tomato plants. B: a video of one gardener's tomato plant.
Tala compares two sources about plant growth. Which is more reliable, and why?
- A, since experts checked its methods and it tested many plants
- B, since you can see the plant yourself
- A, since journal articles cannot be wrong
- B, since the gardener has grown tomatoes for years and knows them well
Use this
Two sources (invented examples). A: a government agency page with references, last reviewed in 2024. B: a page from a group that sells garden products, with no date.
Zee compares two pages about soil. Which is more reliable, and why?
- B, since it is shorter and easier to read
- Neither, since no website can be trusted
- A, since it is dated, referenced and not selling anything
- B, since a group that sells garden products has no reason to be biased