資訊推薦

• 53. Natural selection acts on__? (A) genotypes；(B) populations；(C) individuals；(D) communities.
• 54. If similarities between two structures in different organisms reflect independent evolution, the
• 55. The observation that most aquatic vertebrates (e.g. fish, penguins, and whales) have streamlined
• 56. The enzyme that HIV uses to copy its RNA into DNA is__? (A) Reverse transcriptase；(B) RNA polyme
• 57. A vaccine against the influenza virus would result in production of antibodies against which of
• 58. Viruses always lack which of the following? (A)an envelope；(B) organelles；(C) genetic material；(
• 59. A microbiologist Gram stains a bacterium and finds the bacterium to be pink to red in color, thi
• 60. Escherichia coli and Salmonella can live in our intestines in the presence or absence of oxygen.
• 61. A gaseous hormone produced by plants that helps control fruit ripening is__? (A) dextrose；(B) ca
• 62. If a plant exhibits determinate growth, the plant__? (A) produces auxiliary roots to help stabil
• 63. The _____ transports water and dissolved minerals from the roots of the plant to the shoots of t
• 64. The _____ and _____ of a plant's leaf help conserve water in a plant. (A) root hairs； stoma
• 65. If water is abundant, a plant's guard cells will____ and the stomata will_____. (A) swell；
• 66. The whorl of a flower that consists of all the sepals is the__? (A) stamen；(B) calyx；(C) carpel；
• 67. The plant hormone that stimulates cell division in seeds and fruits is__? (A) auxin；(B) cytokini
• 68. In biology lab, your teacher places petri dishes on the lab table. Upon examination, you observe
• 69. Which phrase defines smooth muscle? (A) used for slow, involuntary movements；(B) used to move bo
• 70. The systems that coordinate communication are__? (A) skeletal and muscular；(B) circulatory and r
• 71. Which of the following best describes how a neuron fires? (A) Na+ ions cross the plasma membrane
• 72. If you had a friend who was unable to see color, you would expect that your friend's eyes h
• 73. Observing a patient who has been given an experimental drug, you notice that it constricts blood
• 74. A fast-twitch muscle fiber__? (A) uses ATP quickly in short, fast contractions；(B) has many capi
• 75. Systolic pressure reflects the__? (A) contraction of the atria；(B) relaxation of the atria；(C) c
• 76. People are often noted to pick up and \"adopt\" a baby wild animal, which then leads
• 77. An ecosystem is defined as__? (A) all of the individuals of the same species living in an area；