The major two forms of polynucleotide secondary structure helices are called A and B . Which statements about the B form are true? B -form helix is right-handed. B-form helix has on average 10.5 base pairs per turn. B-form helix has a rise of 0.34 nm . B-form helbx is formed by double stranded RNA molecules. View Avaltable Mint(s) 1,2 , and 3 1, 2, and 4 1 and 2 All statements are true.