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Courses/Searching for life with evidence/Final challenge

Your learning path

6 lessons

Follow the lessons in order, or revisit any topic.

0 of 6 lessons complete

— / 530 pointsEarned in this course

01early Earth and biosignaturesRead a possible biological trace in context10 min · Read · Practice
02Mars as a case studyEvaluate a Martian candidate without skipping steps10 min · Read · Practice
03ocean worldsFollow ocean evidence through a plume10 min · Read · Practice
04atmospheric clues and false positivesTrace an atmospheric clue back to its source10 min · Read · Practice
05technosignatures and search limitationsDefine what a technology search could detect10 min · Read · Practice
06evaluating a possible discovery responsiblyBuild a discovery claim from tests that can fail10 min · Read · Practice

Put it all togetherEvaluate a possible discovery5 questions · 8 min · Final review

No account is needed to learn. Your correct answers keep their earned rewards.

Course contents · 6 lessons + challenge

Your learning path

6 lessons

Follow the lessons in order, or revisit any topic.

0 of 6 lessons complete

— / 530 pointsEarned in this course

01early Earth and biosignaturesRead a possible biological trace in context10 min · Read · Practice
02Mars as a case studyEvaluate a Martian candidate without skipping steps10 min · Read · Practice
03ocean worldsFollow ocean evidence through a plume10 min · Read · Practice
04atmospheric clues and false positivesTrace an atmospheric clue back to its source10 min · Read · Practice
05technosignatures and search limitationsDefine what a technology search could detect10 min · Read · Practice
06evaluating a possible discovery responsiblyBuild a discovery claim from tests that can fail10 min · Read · Practice

Put it all togetherEvaluate a possible discovery5 questions · 8 min · Final review

No account is needed to learn. Your correct answers keep their earned rewards.

Reading size

CompactStandardLarger

Choose a comfortable size for every lesson.

Final review · Put it all together

Evaluate a possible discovery

5 questions · About 8 minutes · Learn at your own pace

Your goalConnect geological context, controls, chemical budgets and search coverage in a five-question evidence review.

Challenge points — / 100

10 per answer + 50 for completing the challenge

0 of 5 answered correctly

Use what you learned across the course. Revisit a lesson whenever you need it; your answers will wait here. Retries never cost points.

1. early Earth and biosignatures

10 points

A carbon isotope pattern is precise and reproducible. What is still needed before treating it as a unique biological signature?

AContextual tests of nonbiological formation, later alteration and contamination.BNo further tests, because precision logically implies biological origin.CA visually appealing reconstruction of the organisms that must have existed.

Revisit: Read a possible biological trace in context →

2. Mars as a case study

10 points

After a matched blank is subtracted, a sample retains a statistically clear chemical response. What conclusion follows directly?

AAll earlier contamination and every abiotic pathway are automatically excluded.BThe sample necessarily contains living organisms rather than preserved or abiotic material.CA net response remains under the blank and uncertainty model; its biological origin is a separate test.

Revisit: Evaluate a Martian candidate without skipping steps →

3. ocean worlds

10 points

A plume mixture has 2 mg/kg of a compound. Its source-derived fraction may be 0.10 to 0.40, with compound-free dilution and no other effects. What source range follows?

AExactly 2 mg/kg, because the mixture measurement eliminates all transport uncertainty.B5 to 20 mg/kg, with the larger value corresponding to the smaller source fraction.C0.2 to 0.8 mg/kg, multiplying the mixture concentration by the fractions.

Revisit: Follow ocean evidence through a plume →

4. technosignatures and search limitations

10 points

A survey finds no signal during a limited radio band and observing schedule. What is the sound report?

AState the covered bands, thresholds, directions, times and transmitter assumptions.BAnnounce that the target cannot host any biological life.COmit observing coverage because the word nondetection already describes every limitation.

Revisit: Define what a technology search could detect →

5. evaluating a possible discovery responsibly

10 points

Why is a second test vulnerable to the same contaminant not automatically an independent confirmation?

AAny pair of numerical results is independent by definition.BA possible shared contaminant means no follow-up experiment could ever improve confidence.CThe shared cause can produce both results and must enter their joint interpretation.

Revisit: Build a discovery claim from tests that can fail →

The connections you made

Bring the whole story together.

Answer all 5 questions correctly to earn the 50-point completion bonus. Your correct answers are kept as you go.

Use Practice again to retry any completed question without changing your result.

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