Read the following excerpt from a student essay. How can the writer best improve his or her sentence fluency? Allergies are quite common. Allergies occur in about two out of every ten Americans. In people with allergies, the immune system is hypersensitive to a harmless substance in the environment. These substances are called allergens and include things like pollen, dust, pet dander, and mold. Reactions to allergens include sneezing; itchy, watery eyes; runny nose; rashes or hives; and feeling tired or sick. by combining the last two sentences by using shorter sentences by adding transitions between shntences by combining repetitive sentences