Question

the us centers for disease control and prevention reports that condoms have been shown to be effective in preventing hiv infection. in a two - year study of couples in which one partner was hiv - positive and the other hiv - negative, no hiv - negative partner was infected when condoms were used correctly and consistently. among couples in which condom use was inconsistent, 10 percent of the hiv - negative partners became infected. -- \condom effectiveness\ which statement best summarizes the effectiveness of condoms in preventing hiv infection?
○ condoms are always effective.
○ condoms are effective if used correctly.
○ condoms are effective if used consistently.
○ condoms are effective if used correctly and consistently.

Explanation:

To determine the best summary, we analyze the provided text:

• The first option "Condoms are always effective" is incorrect because the text shows that inconsistent use led to infections, so they aren't always effective.
• The second option "Condoms are effective if used correctly" is incomplete. The text also emphasizes the importance of consistent use (along with correct use) as inconsistent use led to a 10% infection rate.
• The third option "Condoms are effective if used consistently" is also incomplete. The text states that correct use is also necessary (as the study showed no infections when both correct and consistent use occurred).
• The fourth option "Condoms are effective if used correctly and consistently" matches the information from the text: when condoms were used correctly and consistently, no HIV - negative partner was infected, while inconsistent use led to infections. This option includes both the correct and consistent use factors which are highlighted in the study.

Answer:

D. Condoms are effective if used correctly and consistently.