How might criteria and constraints for an artificial burrow built in a nature preserve compare to one built in an urban area?

Which of the following is an oxidation-reduction reaction? (pictured below)

Which would be an adaptation in a rainforest, but not in a tundra? a. ability to store water for a long time b. fur that blends in with snow c. strong claws for killing prey d. a beak that can dig into thick trees

After fertilization, which type of cellular division is responsible for the growth and development of a complex, multicellular organism?