Which of the following events does not occur during prophase?
a. identifiable chromosomes appear.
b. the nuclear envelope begins to fragment.
c. chromatin in the nucleus condenses.
d. chromosomes replicate themselves.

If scientists are wrong about earth's age based on radioactive material and the decay rates are really much faster, how would nuclear power plants be affected?

Which of the follow describes a disadvantage secondary sources have compared to primary sources?

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.