11. Which of the following motifs is commonly found in many DNA-binding proteins? (A) inverted-repeat (B) double-helix (C) helix-turn-helix (D) stem-and-loop

5. Which of the following statements is INCORRECT for retroviruses? (A) They are enveloped RNA virus. (B) They encode reverse transcriptase and replicate through a DNA intermediate. (C) Some of them produce tumors in the infected animals. (D) Retroviruses include human immunodeficiency virus (HIV) which primarily infects CD8 T cells.