All of the following are causes of being bitten by mosquitoes EXCEPT ______.

Mosquitoes do not randomly perch on just anyone’s body and begin sucking for the most fragrantly appealing humans. Mosquitoes use odor to sort attractive people from the unattractive to find those that are most tasty.
   Researchers found one sure way to stop attracting the little bugs—stop breathing. Mosquitoes can sniff out an attractive target from as far as 40 miles. When humans exhale, they expel a plume of CO(下标)2 and other odors that travel through the air. The appetizing stir is the equivalent of a dinner bell, alerting mosquitoes that a warm meal is within range,
   When a mosquito is trailing an attractive target, it zigzags up the breath plume until it makes contact, landing on the skin and patiently searching for just the right spot to insert its stylet for an eight-to-ten second feeding.
   Perspiration, a barely avoidable human condition, also is a mosquito lure—but only if the sweat has formed bacteria.
   Bathing helps reduce the attractiveness of sticky bodies, but after-bath products don’t. Skin-care products that clean, soften and moisturize not only improve a person’s appearance, they’re also attractive to mosquitoes. Certain medications, including heart and blood pressure medicine, also alter a person’s likelihood of being bitten.
   Scientists conducted the research to explore ’the tastes of mosquitoes and help humans protect themselves from mosquito-borne disease.