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
- One plant given compost grew to 25 cm
- Compost is made from old leaves
- A gardener on a video says compost helped
Bo's claim: "Warm rooms make bread mold appear sooner." Which evidence supports it best?
- A cooking blog with no author or date says warm kitchens grow mold faster
- Slices at 22 °C showed mold in 5 days on average; at 4 °C, in 12 days
- One slice left out on a warm day grew mold
- Mold is a kind of fungus
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
- One bee landed on a purple flower
- Counts on 10 mornings: purple averaged 24 visits, white averaged 6
- Purple is a popular color
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?
- Leaves use light to make sugar, which the plant uses to grow
- Taller plants look healthier
- The bright lamp cost more money, so it must have been the better lamp
- 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?
- The warm bottles made 22 mL of gas
- Warmth speeds up the reactions yeast uses to break down sugar
- Yeast just prefers warm water
- Warm water looks bubblier and fizzier, so the yeast must be working harder
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
- Counter slices showed mold in 5 days
- Warm bread smells more like mold
- Any warm bread will grow mold, wherever it is kept in the house
In a survey of 10 yards, yards with more earthworms had taller grass. Noah asks whether earthworms make grass taller. Which answer is best?
- 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
- Taller grass must be bringing the earthworms
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?
- Tap water harms any plant it touches, so gardens should skip it
- Sunlight also differed, so rainwater may not be the cause
- Rainwater is the cause, since those plants were taller
- 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?
- Both equally, since both are online
- A, since it cites evidence and has nothing to sell
- B, since a store that sells the powder knows its own product well
- B, since it has the most excited reviews
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?
- A, since it is dated, referenced and not selling anything
- B, since a group that sells garden products has no reason to be biased
- B, since it is shorter and easier to read
- Neither, since no website can be trusted