Final answer:
The old communications systems exhibited all of the listed shortcomings, including limited range, vulnerability to interference, inefficient use of frequencies, limited security, lack of encryption, and limited bandwidth. Newer technologies have mitigated many of these issues but have also introduced new challenges such as the digital divide and increased security risks.
Step-by-step explanation:
The shortcomings of the old communications systems are indeed D. All of the above. These include limited range, vulnerability to interference, inefficient use of frequencies, limited security, lack of encryption, and limited bandwidth. With the advent of newer technologies, such as microwave transmission, communications satellites, and other wireless technologies, many of these shortcomings have been addressed. For instance, these technologies allow for greater data capacity and enable clear line of sight communications over longer distances without as much interference.
However, these improvements also come with downsides, such as the digital divide and increased security risks. Additionally, the expansion of communications technologies has posed environmental threats to radio astronomy due to the increase in frequency interference. It's essential that we balance technological advancement with mindfulness towards the impact on various sectors such as security and science.