telephone lines

micro waves

satellites

All of these

divide time into discrete intervals

require global time synchronization

both 1) divide time into discrete intervals and 2) require global time synchronization

none of these

error detection

error correction

synchronization

slowing down the communication

non-persistent then it results in randomised wait and sense

1-persistent then the channel is continually sensed

p-persistent then randomised retransmission is done

both (a) and (b)

TDM

Register insertion

Carrier sense systems

all of these