Annelids have closed circulatory systems, meaning the blood moves through pressurized vessels. find the dorsal blood vessel and the ventral blood vessel. how does blood move from one to the other? blood is pumped by 5 vessels that encircle the esophagus—locate them. what structure in your body are these 5 pumping vessels analogous to? what are some evolutionary advantages of a closed circulatory system, over relying on diffusion through the body wall as in flatworms and nematodes?

the answer is b)3/8x+1

the areas around the equator

oxygen is the first element in group 16 (via) of the periodic table. the periodic table is a chart that shows how chemical elements are related to each other. the elements in group 16 are said to belong to the chalcogen family. other elements in this group include  sulfur, selenium, tellurium,  and  polonium.  the name chalcogen comes from the greek word  chalkos,  meaning "ore." the first two members of the family, oxygen and sulfur, are found in most ores.

oxygen is by far the most abundant element in the earth's crust. nearly half of all the atoms in the earth are oxygen atoms. oxygen also makes up about one-fifth of the earth's atmosphere. nearly 90 percent of the weight of the oceans is due to oxygen. in addition, oxygen is thought to be the third most abundant element in the universe and in the solar system.

a ratio derived from the equality between two different units that can be used to convert from one unit to the other. information obtained from experiments, sometimes called experimental results. the part of the experiment that is affected by the independent variable.