Read these sentences from the passage.

these words sank deep into my heart, stirred up sentiments within that lay slumbering, and called into existence an entirely new train of thought. it was a new and special revelation, explaining dark and mysterious things, with which my youthful understanding had struggled, but struggled in vain. i now understood what had been to me a most perplexing difficulty.

which definition best expresses the connotative meaning of the word youthful as the author uses it in the second sentence?

a. brand new

b. ignorant

c. active

d. sensible

genetics is the study of how dna works, the methodologies defining the new recent technologies allow scientist to have a panoramic view of the entire dna landscape, especially how genomes interact with their environment, including off course, factors outside their organisms.

thus is very possible the existence of both scenarios, where populations of isolated individuals have different genetic traits, and share traits related to genetic mutation, due rats can easily travel overseas using human transport channels. so scientists could get a vast number of data, including human interaction, evolution of rodents, health development, spread of infections, development of new organisms, how genomes evolve in different environments and so on.