Which of the following contraceptive methods involves the use of chemicals to kill sperms?
Spermicidal creams contain chemicals that kill sperms, thereby preventing fertilization. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Human Reproduction and Reproductive Health, Topic: Gametogenesis, menstrual cycle and reproductive strategies.