The answer is <span>hy<span>pothalamus.</span></span>
<span>The hy<span>pothalamus <span>regulates the </span></span></span><span>sympathetic nervous system, part of </span><span> autonomic nervous system, </span><span>associated with fight-or-flight </span><span>responses.
During stress situations the sympathetic nervous system is more activated, causing a response of either run or fight. Because of that, the body needs to be prepared and there will be elevated blood pressure (the blood is going more to the skeletal muscle, heart,etc), dilated pupils (for better peripheral vision) and increased respiration. </span>
<u><em>Species</em></u> is the category that can mate and produce fertile offspring.
A relatively small blood pressure gradient is generally insufficient to move blood through the veins under given conditions, thus venous return must be facilitated by valves within veins and two "pumps." ... As skeletal muscles contract, veins are squeezed to help propel the blood toward the heart.
