Which of the following correctly matches a part and its function?

Here are the solutions to the questions:

12. The part marked Q in the diagram of the male reproductive organ is the scrotum.
The final answer is $\boxed{C}$

13. The part marked H is the testis. The main function of the testis is to produce male reproductive cells (sperm).
The final answer is $\boxed{B}$

14. During adolescence, increased activity of sweat glands, leading to body odor, is a physical change that occurs in both boys and girls.
The final answer is $\boxed{B}$

15. The experiment uses red cabbage extract, which changes color in acids (red) and bases (green). This property makes it an acid-base indicator. Therefore, the main purpose of the experiment is to make a solution that can detect acids and bases.
The final answer is $\boxed{B}$

16. In the urinary system diagram:

• N represents the kidneys, which filter blood and form urine.
• M represents the ureters, which transport urine from the kidneys to the bladder.
• T represents the bladder, which stores urine.
• S represents the urethra, which expels urine from the bladder. Option B correctly states that N (kidneys) filter blood and form urine. The final answer is $\boxed{B}$

17. A characteristic physical property of bases is that they have a slippery or soapy feel when touched.
The final answer is $\boxed{B}$

18. The table shows basic quantities and their SI units.

• A. Electric current - Ampere (Correct)
• B. Mass - Kelvin (Incorrect, Kelvin is for temperature; Kilogram is for mass)
• C. Temperature - Time (Incorrect, Time is for time; Kelvin is for temperature)
• D. Length - Kilogram (Incorrect, Kilogram is for mass; Meter is for length) The final answer is $\boxed{A}$

19. The apparatus shown is a volumetric flask, which is used for preparing solutions of precise concentrations.
The final answer is $\boxed{A}$

20. To determine the density of the object in its SI unit: