0 votes 0 votes How many $4$-element $RNA$ sequences contain the base $U?$ do not contain the sequence $CUG?$ do not contain all four bases $A, U, C,$ and $G?$ contain exactly two of the four bases $A, U, C,$ and $G?$ Combinatory kenneth-rosen discrete-mathematics counting descriptive + – admin asked Apr 28, 2020 • edited Apr 28, 2020 by Lakshman Bhaiya admin 441 views answer comment Share Follow See all 0 reply Please log in or register to add a comment.