Which of the following effects occurs due to the action of Beta-2 Agonists?

Beta-2 agonists are a class of medications primarily used in the management of respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD). These agents specifically target beta-2 adrenergic receptors located in the smooth muscle of the airways. When activated, these receptors lead to relaxation of these muscles, resulting in bronchodilation. This effect helps to widen the airways, improving airflow and making it easier for patients to breathe.

In contrast, bronchoconstriction is a narrowing of the airways, which would oppose the action of beta-2 agonists. Increased histamine release typically contributes to bronchoconstriction and inflammation, which beta-2 agonists aim to counteract. Fluid retention is not directly related to the primary action of beta-2 agonists and is more associated with other classes of medications such as corticosteroids or certain antihypertensives. Therefore, the action of beta-2 agonists is specifically characterized by their ability to induce bronchodilation, making this the correct answer.