Answer: D) Decrease the window size Explanation: A receiving host can control the transmitter by using flow control ( TCP uses windowing by default). By decreasing the window size, the receiving host can slow down the transmitting host so the receiving host does  not overflow its buffers.

Answer: D) Broadcast Explanation: A transmission to the MAC address ff : ff : ff : ff : ff : ff is a broadcast transmission to all stations.

Answer: C) one broadcast and three collision Explanation: If a switch has three computersconnected to it, with no VLANs present , one broadcast and three collision domains are created.

Answer: D) One broadcast and one collision Explanation: If a hub has three computers connected to it, one broadcast and one collision domain is created

Answer: C) To provide a means for the receiver to govern the amount of data sent by the sender Explanation: Flow control allows the receiving device to control  the transmitter so the receiving device's buffer does not overflow.

The Data Link layer is responsible for the framing of data packets.

The physical layer takes frames from the Data Link layer and encodes the 1s and 0s into a digital signal for transmission on the network medium.

The Network layer provides routing through an internetwork and logical addressing.