43. Testosterone and estradiol are (A) nucleic acids. (B) carbohydrates. (C) proteins. (D) steroids.

2. Genetically engineered plants (A) are more difficult to engineer than animals. (B) include a transgenic rice plant that can help prevent are more difficult to engineer than animals t vitamin A deficiency. (C) are being rapidly developed, but traditional plant breeding programs are still the only method used to develop new plants. (D) are able to fix nitrogen themselves