Final answer:
The result of the adrenal gland releasing epinephrine into the blood is an increase in heart rate, as part of the body's short-term stress 'fight-or-flight' response.
Step-by-step explanation:
The release of epinephrine by the adrenal gland into the blood, often in response to stress, has multiple effects on the body. Given the choices provided, the result of the adrenal gland releasing epinephrine is d. increase in heart rate. When epinephrine circulates in the bloodstream, it triggers several physiological changes: it accelerates the breakdown of glycogen into glucose in the liver and skeletal muscle cells, increases blood glucose levels, elevates the heart rate, and increases blood pressure. This reaction is part of the body's short-term stress response, also known as the 'fight-or-flight' response, which prepares the body to face a perceived threat or to flee from it.