Name urea excess water and ions excreted by kidneys
State all three required kidney excretion categories.
Exam scope and assessment notes
Core and Extended · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
Before you begin
- Recall cell metabolism, blood transport, amino acids and the distinction between excretion and egestion.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which organ forms urine from blood processing?
What you will learn
- The kidneys receive blood-carried materials
- Urine carries waste and excess amounts
Name urea excess water and ions excreted by kidneys
Kidneys excrete all three named categories. Urea is one urine constituent; excess qualifies water and ions. Original teaching model.
| Feature | Meaning |
|---|---|
| Metabolic waste | Urea |
| Excess liquid | Water beyond requirements |
| Excess dissolved substances | Ions beyond requirements |
| Mixture | Urine is not pure urea |
The kidneys receive blood-carried materials
The kidneys excrete urea and excess water and ions. Keep all three categories in the answer. Blood supplies substances to the kidneys, and material destined for excretion becomes part of urine. Urea is not a synonym for urine: it is one dissolved constituent of a liquid that also contains water and ions.
Water and ions have essential roles in the body. The required wording is excess water and ions, rather than all water and all ions. Kidney processing allows useful amounts to remain or return to the blood while waste and excess can be removed. The detailed nephron outline is a Supplement requirement taught later in this section.
Urine carries waste and excess amounts
Kidneys form urine, ureters carry it towards the bladder, the bladder stores it, and the urethra is the route out of the body. These functions distinguish the processing organs from the tubes and storage organ. The urinary bladder does not replace the kidneys as the organs that perform the required blood processing.
Do not infer a person’s kidney function from urine colour, an isolated quantity or a written practice answer. The examples here teach named materials and organ roles, with invented records where calculation is useful. The required statement identifies kidney excretion, while laboratory assessment and medical interpretation require evidence beyond this learning model.
Pause and explain
Which kidney excretion list is complete?
Worked example
List the three required categories excreted by kidneys.
Show the worked solution
- Include the named nitrogenous waste.
- Qualify water and ions as excess.
Answer Urea, excess water and excess ions.
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Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
State the materials excreted by kidneys in this syllabus.
Give me a hint
Include three categories and the excess qualifier.
Compare my reasoning
- Name urea.
- Add excess water and ions.
The kidneys excrete urea, excess water and excess ions.
Look for these in your work
- Name all three
- Qualify water and ions
Correct: urine and urea are two names for the same pure substance.
Give me a hint
One is a mixture and the other a constituent.
Compare my reasoning
- Urine includes water and dissolved substances.
- Urea is one constituent.
Urine is a liquid mixture containing urea, water and ions; urea is one dissolved substance, not another name for the whole urine.
Look for these in your work
- Distinguish mixture and constituent
- Name additional components
A diagram shows urine stored in the bladder. Does that make the bladder the organ that processes blood to form it?
Give me a hint
Storage and formation are different roles.
Compare my reasoning
- Kidneys form urine by processing blood.
- Bladder stores it after transport.
No. Kidneys perform blood processing and form urine; the bladder stores the urine received through ureters.
Look for these in your work
- Separate formation and storage
- Give the correct organ roles
Common mistakes
- Equating urea with all urine.
- Omitting the word excess for water and ions.
What can you explain now?
Which kidney excretion list is complete?
Compare with the explanation
Urea, excess water and excess ions
All three required categories are present.
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Make it stick
State all three kidney excretion categories with the correct qualifier.
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