An isolated system is best characterized as a system in which: energy can freely enter and leave but matter cannot. matter and energy can freely enter and leave. matter can freely enter and leave, but energy cannot. energy and matter cannot enter or leave.

Sea stars, sea urchins, sand dollars, and brittle stars are all memeber of a group, what is the common name of the group they are all in

1. an enzyme is considered a(n) because it speeds up a chemical reaction without being used up.2. in a catalyzed reaction, a reactant is often called a(n) . an enzyme is specific because the shape of its matches only particular reactants.4. an enzyme speeds up reactions by lowering the . the between an active site and its substrate often strains bonds and the reaction proceed.6. a( , which is often a vitamin, binds to an enzyme and plays a role in catalysis.7. high temperatures or changes in ph can an enzyme, causing it to lose its shape and biological activity.

What is a group of organisms called