47. During kidney dialysis, blood and a dialyzing solution are separated by a semipermeable membrane. For kidney dialysis to work properly, the dialyzing solution should contain 
(A) a lower solute concentration than blood
(B) a higher concentration of urea than blood 
(C) a lower glucose concentration than blood
(D) a lower concentration of urea than blood 
(E) a much smaller volume of fluid than the blood passing through it 

43. An area of habitat where a population's reproductive success exceeds mortality is (A) the results of edge effect (B) going to occur speciation very soon (C) a source habitat to the population (D) going to decrease population size (E) the effective size of the population

44. Which of the following is an INCORRECT statement about fungi? (A) they are heterotrophs (B) most of their bodies are constructed of hyphae : (C) their cell walls mainly consist of cellulose (D) they are more closely related to animals than plants (E) they serve as decomposers in communities £

45. Fermentation is essentially glycolysis plus an extra step in which pyruvic acid is reduced to form lactic acid or alcohol ; and carbon dioxide. This last step 養 (A) removes poisonous oxygen from the environment (B) extracts a bit more energy from glucose [ (C) enables the cell to recycle NAD+ (D) inactivates toxic pyruvic acid (E) enables the cell to make pyruvic acid 奪 into substances it can use [

46. A biologist isolated a gene from a human cell, attached it to a plasmid, and inserted the plasmid into a bacterium. The I； bacterium made a new protein, but it was nothing like the protein normally produced in a human cell. Why? ; (A) the bacterium had undergone transformation (B) the gene did not have sticky ends 誓 (C) the gene contained introns (D) the gene did not come from a genomic library ; (E) the biologist should have cloned the gene first ^

48. It takes much longer for sex hormones and other steroids to produce their effects than it takes for nonsteroid hormones. ; Why? | (A) steroids are bigger, slower molecules (B) steroids usually must be carried longer distances by the blood ^ (C) steroids cause target cells to make new proteins, which takes time (D) steroids must relay their message via a ; second messenger (E) it takes longer for endocrine cells to make and secrete steroids ^

49. A peak in_triggers ovulation on about the_day of the monthly cycle. [ (A) progesterone ... fourteenth (B) LH ... seventh (C) FSH ... second (D) LH .. .fourteenth | (E) estrogen ... twentieth

50. Mitosis and cytokinesis result in the formation of_, meiosis and cytokinesis result in the formation of_. (A) 4 diploid cells ... 4 haploid cells (B) 2 diploid cells …2 hap]oid cells (C) 2 diploid cells ... 4 haploid cells | (D) 2 diploid cells ...2 diploid cells (E) 4 haploid cells ...2 diploid cells |：

51. During the early development of a human embryo the_________eventually forms_________. (A) blastocoel ... arch enter on (B) epiblast...ectodermal, mesodermal, and endodermal tissues (C) epiblast... placenta (D) trophoblast... embryo proper (E) hypoblast ... amniotic cavity

52. You would expect a cell with an extensive Golgi apparatus to (A) make a lot of ATP (B) secrete a lot of material (C) move actively (D) perform photosynthesis (E) store large quantities of food

53. In a laboratory, a scientist feeds yeast cells sugar made with radioactive carbon and keeps oxygen gas out of the container. In which substance will the radioactive carbon appear first? (A) water (B) phospholipids (C) pyruvate (D) carbon dioxide (E) electron transport molecules