Which cultural groups control the most fertile lands?
a. government leaders
b. subsistence farmers
c. traders and herders
d. craft workers

Most probably the government or letter a.  Government takes charge of distributing land to others especially farmers who work the land.  Government plays a big role especially when it comes to lands that have the potential to grow good crops.

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.

show options, then i will gladly answer you question.

have a good day.