Use the data in Table.I to answer question 48.
The data were obtained from a study of the length of tirne spent in each phase of the cell cycle by cells of three eukaryotic organisms designated beta, delta, and gamma.

48. The best conclusion concerning delta is that the cells
(A) contain only one chromosome that is very short.
(B) contain no DNA.
(C) contain no RNA.
(D) divide in the G₁ phase.
(E) are actually in the G₀ phase.

44. Hormone X produces its effect in its target cells via the cAMP second messenger system. Which of the following will produce the greatest effect in the cell? (A) a molecule of hormone X injected into the cytoplasm of the cell (B) a molecule of activated, cAMP-dependent protein kinase injected into the cytoplasm of the cell (C) a molecule of cAMP injected into the cytoplasm of the cell (D) a molecule of hormone X applied to the extracellular fluid surrounding the cell (E) a molecule of cAMP applied to the extracellular fluid surrounding the cell

45. It is very difficult to sneak up to a grasshopper and catch it. Why? (A) They have binocular vision. (B) They have excellent hearing for detecting predators. (C) They have compound eyes with multiple ommatidia. (D) They have a camera-like eye with multiple fovea. (E) They have eyes with multiple fovea.

46. Which of the following is the best explanation for the inability of an animal cell to reduce the concentration in its cytosol compared with the extracellular fluid? (A) low oxygen concentration around the cell (B) loss of transcription factors (C) low levels of protein kinase in the cell (D) blockage of the synaptic signal (E) insufficient ATP levels in the cytoplasm

47. All of the following represent adaptations by terrestrial animals to drying conditions except (A) salt glands. (B) increased thirst. (C) efficient kidneys. (D) anhydrobiosis. (E) impervious surfaces.

49. Which of the following is a characteristic of the early stages of local inflammation? (A) attack by cytotoxic T cells (B) release of histamine (C) fever (D) antibody- and complement-mediated lysis of microbes (E) arteriole constriction

50. Which of the following is not a component of an insect's defense against infection? (A) phenoloxidase activation, leading to the formation of large deposits around parasites (B) production of antimicrobial peptides (C) activation of natural killer cells (D) a protective exoskeleton (E) phagocytosis by hemocytes

51. sexual reproduction and sexual reproduction are different in that (A) individuals reproducing asexually transmit 100% of their genes to their progeny, whereas individuals reproducing sexually only transmit 50%. (B) asexual reproduction produces offspring that are genetically identical to the parents, whereas sexual reproduction gives rise to genetically distinct offspring. (C) asexual reproduction involves a single parent, whereas sexual reproduction involves two. (D) asexual reproduction only requires mitosis, whereas exual reproduction always involves meiosis. (E) all of the above

52. Referring to a plant sexual life cycle, which of the following terms describes the process that leads directly to the formation of gametes? (A) sporophyte meiosis (B) gametophyte mitosis (C) gametophyte meiosis (D) sporophyte mitosis (E) alternation of generations

53. The F1 offspring of Mendel's classic pea cross always looked like one of the two parental varieties because (A) one allele was completely dominant over another. (B) each allele affected phenotypic expression. (C) the traits blended together during fertilization. (D) no genes interacted to produce the parental phenotype. (E) different genes interacted to produce the parental phenotype.

54. Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. This suggests (A) that the parents were true-breeding for contrasting traits. (B) incomplete dominance. (C) that a blending of traits has occurred. (D) that the parents were both heterozygous. (E) that each offspring has the same alleles.