68. One striking difference between development in plants and development in animals is the importance of cell in animal embryos.
(A) division
(B) differentiation
(C) growth
(D) movement
(E) death

64. Why do histones bind tightly to DNA? (A) Histones are positively charged, and DNA is negatively charged. (B) Histones are negatively charged, and DNA is positively charged. (C) Both histones and DNA are strongly hydrophobic. (D) Histones are covalently linked to the DNA. (E) Histones are highly hydrophobic, and DNA is hydrophilic.

65. What is the enzymatic function of restriction enzymes? (A) to add new nucleotides to the growing strand of DNA (B) to join nucleotides during replication (C) to join nucleotides during transcription (D) to cleave nucleic acids at specific sites (E) to repair breaks in sugar-phosphate backbones

66. Bacteria containing recombinant plasmids are often identified by which process? (A) examining the cells with an electron microscope (B) using radioactive tracers to locate the plasmids (C) exposing the bacteria to an antibiotic that kills cells lacking the plasmid (D) removing the DNA of all cells in a culture to see which cells have plasmids (E) producing antibodies specific for each bacterium containing a recombinant plasmid.

67. A eukaryotic protein can be made in bacteria by inserting the gene encoding the protein into a(n) (A) protein plasmid. (B) expression vector. (C) yeast artificial chromosome (YAC). (D) PCR vector. (E) restriction plasmid.

69. A cell that remains entirely flexible in its developmental possibilities is said to be (A) differentiated. (B) determined. (C) totipotent. (D) genomically equivalent. (E) epigenetic.

70. Catastrophism, meaning the regular occurrence of geological or meteorological disturbances (catastrophes), was Cuvier's attempt to explain the existence of (A) evolution. (B) the fossil record. (C) uniformitarianism. (D) the origin of new species. (E) natural selection.

71. "Improving the intelligence of an adult through education will result in that adult's descendants being born with a greater native intelligence." This statement is an example of (A) Darwinism. (B) Lamarckism. (C) uniformitarianism. (D) scala naturae. (E) Malthusianism.

72. Even in Darwin's time, the blending hypothesis was incompatible with observed facts. If the blending hypothesis were true, then what should one expect to observe over the course of generations? (A) Phenotypic polymorphisms should increase. (B) Genetic variation should increase. (C) Members of a breeding population should become more uniform in phenotype. (D) Neutral variation should decrease. (E) Genetic polymorphisms should increase.

73. Successfully breeding two individual organisms at a zoo and obtaining fertile offspring for several generations is no guarantee that the same could occur in nature (i.e., in the wild). Which species concept becomes difficult to confirm because of this fact? (A) biological (B) ecological (C) morphological (D) phylogenetic (E) paleontological

74. Which of the following is not considered an intrinsic isolating mechanism? (A) sterile offspring (B) ecological isolation (C) geographic isolation (D) gametic incompatibility (E) timing of courtship display