Hello!
The answer to your question is A.
Discovery of codons.
~Hope this Helps!~
I'm not sure, we did in class, is to make a blue print of all life and rna is made as well. D NA is double stranded, if this not the answer i can look in my notes.
Answer:
Xylem carries water and minerals from the roots to the leaves. Whereas, phloem carries the food prepared by the leaves to different parts of the plant.
Explanation: