Judge a biology claim: evidence, reasoning and reliable sources
Grade 9 Science Worksheet
Circle the best answer.
Bo's claim: "Warm rooms make bread mold appear sooner." Which evidence supports it best?
- Slices at 22 °C showed mold in 5 days on average; at 4 °C, in 12 days
- Mold is a kind of fungus
- One slice left out on a warm day grew mold
- 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?
- Counts on 10 mornings: purple averaged 24 visits, white averaged 6
- A garden shop near the school sells more purple flower seeds than white ones
- Purple is a popular color
- One bee landed on a purple flower
Read this first
Bean seedlings after 14 days (example data)
Lamp Plants Mean height (cm) bright 10 18 dim 10 10 Jun's claim: bright light helped the seedlings grow taller. Which reasoning links the evidence to the claim?
- The bright lamp cost more money, so it must have been the better lamp
- Taller plants look healthier
- Leaves use light to make sugar, which the plant uses to grow
- The plants averaged 18 cm and 10 cm
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?
- Yeast just prefers warm water
- Warmth speeds up the reactions yeast uses to break down sugar
- Warm water looks bubblier and fizzier, so the yeast must be working harder
- The warm bottles made 22 mL of gas
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?
- Mold is alive, and warmth speeds up the reactions in its cells
- Any warm bread will grow mold, wherever it is kept in the house
- 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?
- The survey settles that feeders help flowers
- They rise together, but another factor, like care or sunlight, could explain both
- More feeders went with fewer flowers
- The feeders cause the blooms, since both go up
In a survey of 10 yards, yards with more earthworms had taller grass. Noah asks whether earthworms make grass taller. Which answer is best?
- Taller grass must be bringing the earthworms
- The data show no link between the two
- Earthworms cause taller grass, since both rise together
- The survey shows a link, not a cause; a controlled test is needed
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 has no effect on plant growth
- Tap water harms any plant it touches, so gardens should skip it
- Rainwater is the cause, since those plants were taller
- Sunlight also differed, so rainwater may not be the cause
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?
- Both equally, since both are online
- A, since it cites evidence and has nothing to sell
- B, since it has the most excited reviews
- B, since a store that sells the powder knows its own product 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?
- Neither, since no website can be trusted
- B, since it is shorter and easier to read
- B, since a group that sells garden products has no reason to be biased
- A, since it is dated, referenced and not selling anything