Why are there republican debates and caucuses week after week, but none

[SpacedFrehley]

for democrats? why not dem vs. rep? I couldn't fit the word independent in my question: but them as well? We have seen months of Republican debates and nothing from Democrats? I am not a guru on politics. What are the current "caucuses about?" why do these primaries matter? What other Democrats will run for office? Why are there no Democrat debates? Why no Dem vs Rep vs Independet debates?

I majored in math not politics.