Question

Reactions can range from mild to severe. When a reaction occurs, the body releases a chemical called histamine into the bloodstream. Histamine causes symptoms such as an itchy skin rash or nasal congestion. It can also cause wheezing, coughing, stomach pain, and vomiting. A very severe reaction can include difficulty breathing and heart problems. The ________ of reactions can vary.
Aprecision Bsources
Cextent Dphases

Answer 1

C — "extent" fits best; it means the degree or severity of reactions, which can vary in the described way.