During a stress response: A. Norepinephrine is released as a neurotransmitter in the brain

B. The sympathetic branch of the autonomic nervous system is activated

C. The adrenal gland releases steroid hormones

D. An increased output of the heart increases blood flow to the muscles

The carbon cycle is best defined as a process in which a. carbon changes from inorganic forms to organic forms and back b. carbon is changed into other elements such as oxygen or nitrogen c. carbon is continually created from the sun’s energy by plants d. carbon is consumed and regenerated from other elements such as oxygen and nitrogen