Question

Which of the following is an excretory organ of the human body?

• A. Kidney
• B. Lungs
• C. Skin
• D. All of these

Hint:

Major excretory organs and their wastes:
Kidneys → Urine (urea, excess water, salts)
Lungs → Carbon dioxide, water vapor
Skin → Sweat (water, salts, small amount of urea)
Liver → Bile pigments
Large intestine → Feces

Answer 1

The Correct Option is D

Step 1: Understanding excretion.
Excretion is the process of removing metabolic waste products and excess substances from the body. Several organs participate in this process.
Step 2: Major excretory organs and their waste products.

Kidney: Primary excretory organ. Removes nitrogenous wastes (urea, uric acid, creatinine), excess water, salts, and toxins through urine.
Lungs: Remove carbon dioxide and water vapor (as waste products of respiration) through exhalation.
Skin: Removes water, salts, and small amounts of urea through sweat (via sweat glands).
Liver: Removes bile pigments (bilirubin), cholesterol, and toxins through bile.
Large intestine: Removes solid waste (feces) containing undigested food, bacteria, and some metabolic wastes.
Step 3: Analysis of each option.

(A) Kidney: This IS an excretory organ. Kidneys are the main organs of excretion.
(B) Lungs: This IS an excretory organ. Lungs excrete carbon dioxide and water vapor.
(C) Skin: This IS an excretory organ. Skin excretes sweat containing water, salts, and urea.
(D) All of these: Correct. Kidneys, lungs, and skin are all excretory organs.

Final Answer: (D) All of these.