Excretion Practice Questions
WAEC (West Africa) · WAEC Biology · 134 free MCQs with instant results and detailed explanations.
134
Total
37
Easy
66
Medium
31
Hard
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Sample Questions from Excretion
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
In plants, which of the following processes is primarily associated with excretion?
A.
Transpiration
B.
Photosynthesis
C.
Respiration
D.
Absorption
Show Answer & Explanation
Correct Answer: A
Transpiration is the process through which plants lose excess water and certain waste products, thus functioning as a method of excretion.
Q2
Easy
What is the main purpose of excretion in living organisms?
A.
To eliminate toxic substances
B.
To produce energy
C.
To store nutrients
D.
To promote growth
Show Answer & Explanation
Correct Answer: A
The main purpose of excretion is to eliminate toxic substances and waste products from the body, thus option A is correct.
Q3
Easy
Which organ in the human body is primarily responsible for the excretion of urea?
A.
Liver
B.
Kidney
C.
Lungs
D.
Skin
Show Answer & Explanation
Correct Answer: B
The kidneys are the primary organs responsible for filtering blood and excreting urea, a waste product formed from the breakdown of proteins.
Q4
Medium
Which organ in the human body is primarily responsible for filtering blood to produce urine?
A.
Liver
B.
Kidney
C.
Bladder
D.
Lung
Show Answer & Explanation
Correct Answer: B
The kidney is the primary organ responsible for filtering blood, removing waste products, and producing urine.
Q5
Medium
What is the main nitrogenous waste product excreted by mammals?
A.
Uric acid
B.
Ammonia
C.
Urea
D.
Creatinine
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Correct Answer: C
Mammals primarily excrete urea, which is less toxic than ammonia and requires less water for excretion compared to uric acid.
Q6
Medium
Which process describes the movement of water and solutes from the blood into the kidney tubules?
A.
Reabsorption
B.
Filtration
C.
Secretion
D.
Excretion
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Correct Answer: B
Filtration is the process where blood is filtered in the glomerulus, allowing water and solutes to pass into the kidney tubules.
Q7
Medium
Which of the following correctly describes the role of the liver in excretion?
A.
Filters blood to produce urine.
B.
Converts ammonia to urea.
C.
Regulates body temperature.
D.
Absorbs nutrients from food.
Show Answer & Explanation
Correct Answer: B
The liver converts ammonia, a toxic byproduct of protein metabolism, into urea, which is less toxic and can be excreted by the kidneys.
Q8
Hard
Which of the following structures in the human kidney is primarily responsible for the filtration of blood?
A.
Bowman's capsule
B.
Glomerulus
C.
Loop of Henle
D.
Renal pelvis
Show Answer & Explanation
Correct Answer: B
The glomerulus is a network of capillaries surrounded by Bowman's capsule, and it is specifically responsible for the filtration of blood, allowing water, ions, and small molecules to pass into the nephron while retaining larger molecules like proteins in the bloodstream.
Q9
Hard
A patient with diabetes insipidus has difficulty concentrating urine. Which of the following hormones is most likely affected in this condition?
A.
Aldosterone
B.
Antidiuretic hormone (ADH)
C.
Cortisol
D.
Insulin
Show Answer & Explanation
Correct Answer: B
Diabetes insipidus is characterized by a deficiency of antidiuretic hormone (ADH), which is responsible for promoting water reabsorption in the kidneys. Without sufficient ADH, the kidneys cannot concentrate urine effectively, leading to excessive urination and thirst.
Q10
Hard
Which of the following processes primarily occurs in the nephron to regulate blood pH?
A.
Reabsorption of bicarbonate ions
B.
Filtration of blood
C.
Secretion of hydrogen ions
D.
Excretion of urea
Show Answer & Explanation
Correct Answer: C
The secretion of hydrogen ions in the nephron helps maintain the acid-base balance, thus regulating blood pH effectively.
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Excretion — WAEC (West Africa) WAEC Biology Practice Questions Online
This page contains 134 practice MCQs for the chapter Excretion in WAEC (West Africa) WAEC Biology. The questions are organized by difficulty — 37 easy, 66 medium, 31 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.