While fishing from the banks of the Missouri River in eastern Montana, you notice some shiny fragments of fossils lying in the grey shaly mud of the banks. The nearby outcrops are known to be composed of Cretaceous strata. Upon closer inspection, you discover that the fragments were from a coiled "critter" that had very ornate "curved" lines across the very shiny pearly or lustrous outer layer. Required:
What is this fossil "critter"?

the wrong statement is - c. a desert had more biodiversity than a marsh.

the deserts are one of the places of the planet where there's the least biodiversity. the reasons for that are the climate and the lack of food sources, which hampers both the number of the species that can survive in it, and the number of the individuals in the species itself.

the marshes, on the other hand, are places where there's perfect conditions for lots of organisms to thrive. the temperature is moderate and nice, the amount of water and the food sources are on a high level, so there's an abundance of both plant and animal life in them.