36. What type of network is the Internet primarily based on?
a) Circuit-switched network
b) Datagram network
c) Virtual circuit network
d) Packet-switched network

37. What is the primary disadvantage of asynchronous serial transmission?
a) High error rate
b) Low speed
c) Complex implementation
d) Lack of synchronization

38. How does delta modulation handle changes in analog signals?
a) By quantizing each sample
b) By sampling at fixed intervals
c) By comparing with previous values
d) By encoding changes directly

39. Which method of switching treats each packet as a distinct entity?
a) Circuit switching
b) Datagram switching
c) Virtual circuit switching
d) Packet switching

40. What is the primary advantage of phase shift keying over ASK and FSK?
a) Bandwidth efficiency
b) Power efficiency
c) Speed
d) Error correction