It represents innocence, since the speaker in the poem is sold as a slave.
There are three types of RNA involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribisomal RNA (rRNA). All three of these nucleic acids work together to produce a protein. The mRNA takes the genetic instructions from the nucleus to the cytoplasm, where the ribosomes are located.
Answer:
One advantage of models is that all the mice are exactly alike except for color, enabling the control of all variables except the one being studied. Models are also easier to work with than live mice. One disadvantage of using models is that they do not have the same smell and behaviors as real mice.
Another advantage is that models can be reused for the experiment for a longer period of time with less maintenance.