modern 100Base T Ethernet is implemented using star topologies with full duplex links. how this can give?

Question

how this can give rise to better throughput in terms of probability of collision. Where do the collision occur?

Answer 1

Today's star topologies are connected via an active switch, which eliminates collisions...thus higher throughput.

If you use a passive hub instead, yes, you will have collisions as more and more devices are added to the lan...along with exponential backoffs and slower throughput.