Students in Trinidad investigated vehicle emissions at a busy intersection in Port of Spain. They detected high levels of a colourless, odourless gas that reduces the oxygen-carrying capacity of blood. Which gas did they detect?

Q: How do I try a free CXC Integrated Science question?

Just tap any of the four options on this page — no signup, no card, nothing to install. You'll see the correct answer and a full mark-scheme-style explanation within a second. Each visit shows a fresh randomly-picked question from the live CXC CSEC Integrated Science bank, so you can keep refreshing to try different ones before deciding whether to create a free account for daily access.

Q: Is Kramizo really free for CXC Integrated Science students?

Yes — completely free. Every student gets 45 questions a day on the free plan, across any board and any subject, with no card required and no trial countdown. Kramizo's optional Pro plan removes the daily cap and adds analytics, but the free plan is genuinely free forever. We make money from the small percentage of students who choose to upgrade — not from selling data or ads.

Q: Are the Integrated Science questions aligned to the CXC CSEC syllabus?

Every question is written against the published CXC CSEC Integrated Science syllabus and reviewed for accuracy before being added to the bank. We match the command words (state, describe, explain, evaluate), mark allocations, and difficulty tier you'll see on real CXC past papers. Explanations are written in the style of official examiner mark schemes so students learn exactly what marks are being awarded for.

Question

Students in Trinidad investigated vehicle emissions at a busy intersection in Port of Spain. They detected high levels of a colourless, odourless gas that reduces the oxygen-carrying capacity of blood. Which gas did they detect?

Accepted Answer

Carbon monoxide — Award 1 mark for identifying carbon monoxide as the gas that binds to haemoglobin, reducing oxygen transport. A is incorrect — carbon dioxide does not significantly affect haemoglobin's oxygen-carrying capacity. B is incorrect — sulfur dioxide causes respiratory irritation but does not bind to haemoglobin. D is incorrect — nitrogen dioxide is a brown gas that irritates the respiratory system.

Answer

Carbon monoxide

Answer

Sulfur dioxide

Answer

Nitrogen dioxide

Answer

Carbon dioxide

One real Integrated Science question.No signup. 30 seconds.

One real Integrated Science question.
No signup. 30 seconds.