Arteries deliver blood to the body, and veins return blood to the heart. Veins appear blue because of lack of oxygen and the way the light hits our body, and because our eyes play tricks on us.
Explanation:
This is what I have read from different sources and hope it helps you.
If a stimulus to a neuron is great enough, ___<u>t</u><u>h</u><u>r</u><u>e</u><u>s</u><u>h</u><u>o</u><u>l</u><u>d</u>_____ is reached and an action potential is generated.
