When communicating, the sender / receiver chooses the communication medium (or way) in which to convey the message. What is that medium called?

Need with this plz someone me aspa really need with this! asap

Can someone explain this to me clearly plz

On one hand, i aspire to an ivy league vocation: 1 professor of the sciences in higher education. 2 but like noble amphibians that thrive on land and in the stream, 3 i've got another world of which i like to gladly dream. 4 some say that it's abnormal; my affections are exclusive. 5 in science, they say, emotions are something quite elusive. 6 line 3 exemplifies which kind of figurative language? a) hyperbole b) metaphor c) onomatopoeia d) simile