Which of the following is a health effect of hydrogen sulfide?

Labored breathing is indeed a health effect associated with hydrogen sulfide exposure. Hydrogen sulfide is a highly toxic gas that can irritate the respiratory system and affect normal breathing patterns. At low concentrations, it can cause irritation to the eyes and throat, leading to symptoms such as coughing and difficulty breathing. At higher concentrations, it can be even more dangerous and can cause respiratory failure, effectively leading to labored or even cessation of breathing.

When considering the other options, heightened sense of smell is actually misleading and can be harmful; exposure to hydrogen sulfide can initially cause a heightened sense of smell at low levels, but at higher concentrations, it can lead to a loss of smell. Rapid weight gain and internal bleeding are not typically associated with hydrogen sulfide exposure; these symptoms are relevant to other health conditions or toxic exposures. Recognizing the specific symptoms related to hydrogen sulfide is crucial for understanding its dangers and the proper response in emergency situations.