Why is exhortation necessary in worship services?

Which group of chordates does  notpossess true backbones?                 a.  birds      b.  frogs and toads      c.  lampreys      d.  crocodilians

Me with biology endocrine system crossword also image left i need with hw

In the ocean why are the greatest amount of primary producers found in the epipelagic zone and how does that affect biodiversity