What do the telegraph and telephone have in common?
a) Both use the national highway system to communicate.
b) Both require the input of human data to communicate.
c) Both require plutonium to communicate.
d) Both use electricity and radio waves to communicate.

Question

What do the telegraph and telephone have in common?
a) Both use the national highway system to communicate.
b) Both require the input of human data to communicate.
c) Both require plutonium to communicate. 
d) Both use electricity and radio waves to communicate.

anonymous · Answer

I'm pretty sure its's D.  But I'm not sure

anonymous · Answer

They are both ways for people to communicate, so the answer would be B. The first telegraph included smoke signals, which doesn't require electricity.