How can increase farming cause a decrease in bees

Got science homework the question actually says. Bees fed a diet of five different pollens produce more glucose oxidase than bees fed with only one type of pollen. Glucose oxidase preserves honey and food for bee larvae from micro organisms that cause disease.
Explain as fully as you can how an increase in farming may lead to a decrease in bee numbers.
Need this for tomorrow help

Because farms replace a given biosphere with only a handful of differing crops which reduces the biodiversity of a given area. So for the bees to obtain those five different pollens they would need to travel farther distances to achieve what they had before. This comes at the cost of either settling for whatever is available in the immediate area and risk diseases or push the boundaries of their usual gathering spots to get the required pollen at the risk of straining the worker bees and having many get lost/killed.
Probably more reasons like lack of cover and such that puts the hive at risk from predators, but from the wording of your question I'm sure this answer is good enough. :)

Bees need lots of flowers with pollens to produce honey. Increase in farming will deplete their habitat
thus causing a decrease in bees number.

Hey,Bees need nectar from plants to secrete honey and also tree or some place suitable to build it's hive but farming needs plain area...

farming uses pesticides
introduces mono cultures
reduces habitat for flowers

Yes, because farming expose their hive.