How does poor transmission affect response time in LAN?

The main reason here is that the data would have to be resent. If all the data is not being sent, then the other side would have to signal that it didn't get the data and request a repeat.

This is similar to humans speaking. If there is a lot of noise in the room and distance between the speaker and the listener, it may take longer to have a conversation than if the room is quiet and they are standing face to face. So likewise, if the signal is weak or noisy, then there will be dropped packets and the data will have to be resent.