78. Why are viruses referred to as obligate parasites? (A) They cannot reproduce outside of a host cell. (B) Viral DNA always inserts itself into host DNA. (C) They invariably kill any cell they infect. (D) They can incorporate nucleic acids from other viruses.

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

78. Why are viruses referred to as obligate parasites?
(A) They cannot reproduce outside of a host cell.
(B) Viral DNA always inserts itself into host DNA.
(C) They invariably kill any cell they infect.
(D) They can incorporate nucleic acids from other viruses.

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