1. Which of the following is the fluid found in an insect’s open circulatory system?
2. How can flatworms, simple animals with a flat body shape, survive without a circulatory system?
3. Fishes have:
4. Blood pressure tends to fall with increasing distance that blood has traveled from the heart. Based on this information, which of the following lists the types of blood vessel, in order, from highest blood pressure to lowest?