58. A gastrovascular cavity, with a single opening, is the characteristic digestive system of animals in which phylum?
(A) Nematoda
(B) Platyhelminthes
(C) Arthropoda
(D) Mollusca
(E) Porifera

54. The following organism with the greatest number of Hox genes should be a(n) (A) fish. (B) fly. (C) flatworm. (D) fluke. (E) fruit fly.

55. Which of the following does not have a coefficient of relatedness of 0.5 in humans? (A) a brother to his brother (B) a mother to her son (C) an uncle to his nephew (D) a father to his daughter (E) a sister to her brother

56. Which of the following is true in the logistic model of population growth? (A) as N approaches K, the growth rate will approach zero (B) as N approaches K, the death rate decreases (C) as N approaches K, the carrying capacity of the environment will increase (D) as N approaches K, the growth rate increases (E) both C and D are correct

57. The population cycle of the snowshoe hare and its predator indicates that (A) predators are not the only factor controlling the size of prey populations. (B) the two species must have evolved in close contact because one cannot live without the other. (C) both populations are controlled mainly by abiotic factors. (D) the hare populations is r-selected, whereas the lynx population is K-selected. (E) both C and D are correct.

59. Which of the following statements about endocrine system is false? (A) Hormones from the adrenal cortex control salt and water balance. (B) An increase in endorphins blocks pain. (C) An iodine deficiency might interfere with the production of thyroxine. (D) Some cells can conduct nerve signals and secrete hormones. (E) Most endocrine glands produce steroid hormones.

60. If two modern organisms are distantly related in an evolutionary sense, then one should expect that (A) they should live in very different habitats. (B) their chromosomes should be very similar. (C) they shares a common ancestor relatively recently. (D) they should share fewer homologous organs than two closely related organisms. (E) they should be members of the same genus.

61. How do cleavage divisions differ from normal mitotic cell divisions? (A) Cleavage divisions occur by meiosis, not mitosis. (B) Cleavage divisions are slower than normal cell divisions. (C) Cleavage divisions occur without much mRNA synthesis. (D) Cleavage divisions divide cells into daughters with different gene sets. (E) Both C and D are correct.

62. The endoplasmic reticulum and Golgi apparatus are very similar among the groups of alga-like protists, but chloroplasts differ significantly and appear to be related to different prokaryotes. These facts imply that (A) The Golgi apparatus evolved before the endomembrane system. (B) Chloroplasts evolved before the endoplasmic reticulum. (C) Endomembrane systems evolved before chloroplasts. (D) Endomembrane systems evolved from symbiotic prokaryotes. (E) Both C and D are correct.

63. In the presence of an antibiotic prokaryotic translation can initiate, but only dipeptides that remain bound to the ribosome are formed. This antibiotic appears to block (A) binding of fMet-tRNAi to P site. (B) binding of aminoacyl-tRNA to A site. (C) peptide bond formation. (D) translocation. (E) termination.

64. According to the wobble rules, a tRNA with the anticodon 5'-GAU-3' can recognize the codons (A) 5'-CUA-3' and 5'-UUA-3'. (B) 5'-CUA-3' and 5'-CUG-3'. (C) 5'-AUC-3' and 5'-GUC-3'. (D) 5'-AUC-3' and 5'-AUU-3'. (E) 5'-IUC-3'.