Why do veins also have valves? to keep the blood from circulating too fast
to regulate contractions of the heart
to keep the veins from losing blood
to prevent gravity from pulling the blood towards the feet

In at least 150 words, discuss the meaning of the title, "two kinds". explain the relationship between the title and the theme of the story

As you sit in the library with your friend studying for your weekly quiz on the integumentary system, you come upon an article about the hazards of prolonged exposure to the sun's rays. your curious nature leads you to research the subject further. you're fascinated to learn that minimal exposure to the sun allows you skin to manufacture vitamin d, which is important to maintain homeostasis. you also read that although sunscreen can protect you from the ultraviolet (uv) rays of the sun, some medications can actually increase a person's sensitivity to the sunlight.

Which area of the brain controls the body's ability to fight off stress? question 1 options: synapse, frontal lobe, dendrite, sympathetic nervous system