What is the primary difficulty of organizing earth's biodiversity?

Which of the following statements is true of enzymes? a)they dont provide an active site for substrates to bind in a reaction b)they act on a specific type of substrate in a reaction c)they unusable after a reaction d)they change shape after a reaction

What are two ways that harvesting algae from the ocean may benefit human society? how might the harvest of algae negatively impact the ocean communities where that algae grows? how could this be prevented?

What function does the limb sever in each animal? how are the limb bones of the four animals similar? based on these similarities what can be inferred about the evolution of the four animals.