What does that mean if there is no bifurcations in my time series single cell data? Sorry, 

I have analysed my time series single cell data with Scuba algorithm but that says that there is no bifurcations in my data and outputted a single chain of 4 states with no branching like below figure



Sorry, I googled but I am not quite sure what this means

Any suggestion please?

Thanks a lot
The most obvious interpretation is that the four cell lines are related in a linear pathway rather than a branching one.