Exposure to _________ would most likely result in immediate respiratory distress.

• A. bacterial endotoxins
• B. inhaled allergens
• C. fungal spores
• D. viral DNA fragments

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the nature of each option and how it affects the respiratory system. Bacterial endotoxins are components of the outer membrane of Gram-negative bacteria and can cause inflammation but typically do not cause immediate respiratory distress upon exposure.
2. Step 2: Consider inhaled allergens, which are substances like pollen, dust mites, or pet dander that can trigger an immediate hypersensitivity reaction in susceptible individuals, leading to rapid onset of respiratory symptoms such as wheezing, coughing, or difficulty breathing.
3. Step 3: Evaluate fungal spores, which can cause respiratory issues but usually lead to symptoms after prolonged exposure or in immunocompromised individuals, rather than immediate distress.
4. Step 4: Analyze viral DNA fragments, which are parts of viruses that may stimulate immune responses but generally do not cause immediate respiratory distress upon inhalation.
5. Step 5: Conclude that inhaled allergens are the most likely to cause immediate respiratory distress because they can trigger rapid allergic reactions (Type I hypersensitivity), leading to symptoms such as bronchoconstriction and airway inflammation.