Scientists have discovered that web-spinning spiders spin different kinds of webs, depending on internal cues. spiders fed a daily diet of flies made a web that was not sticky and was used as a home. starving spiders, on the other hand, spun a web that was very sticky in order to catch prey. this behavior shows how the internal stimulus of affects animal behavior and survival.

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.