18. Which statement best expresses the concept of natural selection?
(A) reproductive success influenced by inherited characteristics
(B) inheritance of acquired characteristics
(C) change in response to need
(D) a process of constant improvement, leading eventually to perfection

14. Asthenozoospermia is a medical condition that is characterized by reduced sperm motility. What structure of the sperm is likely affected in a man who has asthenozoospermia? (A) acrosome (B) head (C) middle piece (D) flagellum

15. The gap between the transmitting and receiving neurons in a chemical synapse is known as the (A) node of Ranvier. (B) ion channel. (C) gap junction. (D) synaptic cleft.

16. Which class of sensory receptors responds to stimuli such as touch, pressure, stretching, and sound? (A) thermoreceptors (B) mechanoreceptors (C) electromagnetic receptors (D) chemoreceptors

17. Which part of a bone contains red bone marrow? (A) compact bone (B) fibrous connective tissue (C) spongy bone (D) yellow bone marrow

19. Which description BEST represents the gradual model of speciation (i.e., the formation of new species)? (A) Speciation occurs regularly as a result of the accumulation of many small changes. (B) An isolated population differentiates quickly from its parent stock as it adapts to its local environment. (C) Speciation occurs under unusual circumstances and therefore transitional fossils are hard to find. (D) Species undergo little change over long periods interrupted only by short periods of rapid change.

20. Given the concept of invasive species in ecology and conservation biology, which of the following animals you may see in a forest in Taiwan is an invasive species, one that causes severe ecological damage and needs to be completely removed? (A) A stray dog(遊蕩犬) (B) A Formosan Reeve's muntjac (山羌) (C) A Formosan macaque (台灣獼猴) (D) A Leopard cat (石虎)

1. Which of the following animals displays radial symmetry? (A)a sea anemone (B)a fish (C) a worm (D)an alligator (E)a lobster

2.Geckos are able to walk up walls and across ceilings because of (A)the numerous setae on their toes establish molecular bonds with the surfaces of walls and ceilings. (B)the sticky adhesive secretions on their feet. (C) the little suction cups on their toes. (D)the sticky saliva licked onto the regions where the gecko is about to walk. (E)their sharp toenails that grasp surfaces.

3. In the countercurrent exchange system of fish gills, (A)blood and water are separated by a thick polysaccharide barrier. (B)blood and water flow in the same direction. (C) blood flow in the gills reverses direction with every heartbeat. (D)water flow over the gills reverses direction with every inhalation. (E)blood and water flow in opposite directions.

4.The largest blood vessel in the human body is the (A)pulmonary artery. (B)aorta. (C) vena cava. (D)arteria maxima. (E)superior vena cava.