1. Very rapid speciation occurred when cichlid fishes were isolated in Lake Victoria. Widespread extinction was dramatically seen when ______.
(A) hybridization stopped
(B) fishing was prohibited
(C) predatory fishes were added
(D) artificial selection stopped
(E) insect larvae stocks were depleted

47 What is the main idea of this passage? (A)The ratio of the brain size relative to the body size of an animal is a good measure of intelligence. (B)The number of neurons is an absolute measure of an animal’s intelligence, be it a plant eater or a meat eater. (C)The number of neurons reveals that plant eaters are generally smarter than meat eaters. (D)The ratio of the number of neurons relative to the size of an animal’s body can indicate how smart the animal is.

48 According to the latest study, which of the following statements is true? (A)Dogs are much smarter than most meat eaters, including cats. (B)Cats have more neurons in their brain than other meat eaters, including dogs. (C)The number of a cat’s neurons can double that of a dog’s, and that makes cats better pets for humans. (D)Dogs are quite intelligent and they have as many neurons as humans do.

49 According to the passage, why do plant eaters need to have strong brain power? (A)To find sufficient food to maintain their brain power. (B)To predict possible danger to prevent themselves from being eaten up. (C)To predict possible food sources to support their relatively larger body size. (D)To find safe places to rest to conserve their energy.

50 Which of the following statements can be inferred from this passage? (A)Cats are more intelligent than dogs. (B)Large size meat eating animals tend to sleep a lot. (C)Plant eating animals tend to have a larger brain size. (D)Dogs and cats are suggested to live on a vegetarian diet.

2. Which one of the following statements about endosymbiosis and the origin of the eukaryotic cell are FALSE? (A) Mitochondria are the descendents of purple nonsulfur bacteria. (B) The chloroplasts of red and green alga are the descendents of cyanobacteria. (C) Not all compartments of the eukaryotic cell are derived from the endomembrane system. (D) The brown algae acquired their chloroplasts by engulfing a prokaryotic cell with chloroplasts. (E) None of these choices are correct.

3. Which of the following groups is most threatened by global extinctions? (A) amphibians (B) birds (C) plants (D) mammals (E) fish

4. Irregular dental hygiene and a high sugar diet may lead to tooth decay. Why? (A) Bacteria consume calcium. (B) Glucose forms a weak acid when dissolved in saliva. (C) High concentrations of sugar soften the tooth enamel. (D) Plaque degrades the tooth's protective mucosal layers. (E) Lactic acid fermentation is used to generate ATP under anaerobic conditions.

5. Which of the following regions of the human brain is critically important for controlling heart rate and breathing? (A) medulla oblongata (B) hippocampus (C) cerebellum (D) cerebral cortex (E) thalamus

6. Which of the following correctly indicates the hierarchy of skeletal muscle organization from "small" to "big"? (A) muscle fiber, sarcomere, myofibril, motor unit (B) myofibril, sarcomere, motor unit, muscle fiber (C) sarcomere, myofibril, muscle fiber, motor unit (D) myofibril, sarcomere, muscle fiber, motor unit (E) sarcomere, muscle fiber, myofibril, motor unit

7. The hormones epinephrine and norepinephrine constitute the "alarm" response of the body to stress. What secretes these hormones? (A) pancreas (B) pineal gland (C) thyroid gland (D) adrenal medulla (E) anterior pituitary gland