The basic operation in continuous time is integration, in discrete time it is the time delay of 1 period

Continuous systems with transfer functions of negative relative order are perfectly possible

Once the sampling period is determined, only a discrete (sampled) signal corresponds to a continuous one

There is always only one way of approximating the operation of a continuous system by a discrete one

The main difference between digital and analog systems is that values are discrete in the former (digital) and continuous in the latter (analog)

There is always only one way for a continuous system to replicate the operation of a discrete one

If we discretize our plant with the ZOH method then its input will be step-like, not its output

The rules to draw a discrete root locus are the same as the ones for a continuous one but the interpretation is different