What do scientists believe was the original genetic material able to copy itself without assistance?
A. Proteins
B. Carbohydrates
C. DNA
D. RNA
Answer: D
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The major histocompatibility complex is important in a T-cell's ability to:
A. recognize specific parasites. B. recognize specific bacteria. C. recognize specific viruses. D. recognize self from nonself.
In chickens, females have two different sex chromosomes (Z and W), while the males have two Z chromosomes. A Z-linked gene controls the pattern of the feathers, with the dominant B allele causing the barred pattern and the b allele causing nonbarred feathers. Which of the following crosses would produce all daughters of one type (barred or nonbarred) and all sons of the other type?
A) barred females × nonbarred males B) nonbarred females × barred males C) nonbarred females × nonbarred males D) barred females × barred males E) More than one of the choices is correct.
Unlike most other animals, sponges lack which of the following?
a. a digestive tract only b. a symmetrical body plan only c. tissues only d. a digestive tract and a symmetrical body plan only e. a digestive tract, a symmetrical body plan, and tissues
In the process of glycolysis, glucose is cleaved into a pair of three-carbon ________ molecules.
A. acetyl CoA B. lactate C. oxaloacetate D. pyruvate E. alcohol