With reference to the composition of human urine, consider the following statements: 1. It consists of approximately 95% water. 2. It contains approximately 50% urea. 3. It is devoid of any other waste products. Which of the statements given above is/are correct?

Correct Option The correct option is (a). Explanation Urine is a liquid byproduct of metabolism produced by the kidneys to maintain homeostasis. It serves as the primary vehicle for excreting water-soluble waste products from the bloodstream while regulating the body's fluid and electrolyte balance. Statement-wise Analysis - Statement 1 is Correct: Human urine is predominantly composed of water, which constitutes approximately 95% of its total volume. This high water content is essential for dissolving waste products and facilitating their transport out of the body. - Statement 2 is Incorrect: Urea is the principal nitrogenous waste product in human urine, but it does not constitute 50% of the composition. Instead, urea makes up approximately 2.5% of urine. A concentration of 50% would be biologically impossible and toxic. - Statement 3 is Incorrect: Urine is not devoid of other waste products. Besides water and urea, the remaining 2.5% consists of various other dissolved substances, including uric acid, creatinine, ammonia, and electrolytes such as sodium, potassium, and chloride. Key Takeaway: The composition of human urine is approximately 95% water, 2.5% urea, and 2.5% other waste products (including uric acid, creatinine, and salts).

NCERT Class 7 Science — Chapter 3: Transportation in animals and plants

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With reference to the composition of human urine, consider the following statements:

It consists of approximately 95% water.
It contains approximately 50% urea.
It is devoid of any other waste products.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A1 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

Correct Option

The correct option is (a).

Explanation

Urine is a liquid byproduct of metabolism produced by the kidneys to maintain homeostasis. It serves as the primary vehicle for excreting water-soluble waste products from the bloodstream while regulating the body's fluid and electrolyte balance.

Statement-wise Analysis

Statement 1 is Correct: Human urine is predominantly composed of water, which constitutes approximately 95% of its total volume. This high water content is essential for dissolving waste products and facilitating their transport out of the body.
Statement 2 is Incorrect: Urea is the principal nitrogenous waste product in human urine, but it does not constitute 50% of the composition. Instead, urea makes up approximately 2.5% of urine. A concentration of 50% would be biologically impossible and toxic.
Statement 3 is Incorrect: Urine is not devoid of other waste products. Besides water and urea, the remaining 2.5% consists of various other dissolved substances, including uric acid, creatinine, ammonia, and electrolytes such as sodium, potassium, and chloride.

Key Takeaway: The composition of human urine is approximately 95% water, 2.5% urea, and 2.5% other waste products (including uric acid, creatinine, and salts).

Your note

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Correct Option

The correct option is (a).

Explanation

Statement-wise Analysis

Statement 1 is Correct: Human urine is predominantly composed of water, which constitutes approximately 95% of its total volume. This high water content is essential for dissolving waste products and facilitating their transport out of the body.
Statement 2 is Incorrect: Urea is the principal nitrogenous waste product in human urine, but it does not constitute 50% of the composition. Instead, urea makes up approximately 2.5% of urine. A concentration of 50% would be biologically impossible and toxic.
Statement 3 is Incorrect: Urine is not devoid of other waste products. Besides water and urea, the remaining 2.5% consists of various other dissolved substances, including uric acid, creatinine, ammonia, and electrolytes such as sodium, potassium, and chloride.

Key Takeaway: The composition of human urine is approximately 95% water, 2.5% urea, and 2.5% other waste products (including uric acid, creatinine, and salts).