Hover or tap underlined Spanish terms to see their translation and exam tip.
Acerca de la composición de la atmósfera, marque la opción correcta.About the gas composition of the atmosphere, mark the correct option:
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Correct answer: d) All the above options are false.
Why it is correct
In dry air 78% by volume is nitrogen, 21% is oxygen and about 0.93% is argon, so all the combinations in a, b and c are false.
Why the others are not
- a) Nitrogen is 78% and hydrogen is only a trace gas.
- b) 21% is oxygen, not argon.
- c) Swaps the percentages of nitrogen and oxygen.
How to work it out in the exam
- True dry air: 78% N2, 21% O2, ~1% Ar.
Where this question comes from
- Junta de Andalucía · 2026 · 1ª convocatoria · CY Módulo genérico · question 1 Official paper · Official answer key
Pending instructor review. Machine translation, not reviewed.