USABO Open Exam 2024 questions and answers already graded A+

In certain areas of Sub-Saharan Africa high levels of anemia are exhibited as a consequence of iron deficiency. What other symptom would you expect might be found in these peoples? A. goiter B. decrease in immune function C. high degree of oscillation in blood glucose levels D. scurvy E. reproductive failure B. decrease in immune function Inflammation and injury of the pancreas can cause elevated levels of serum amylase. Injury or disease of which of the following organs might you expect to produce a similar laboratory finding? A. Liver B. Colon C. Thyroid D. Salivary gland E. Adrenal gland D. Salivary gland What process in plants requires darkness? A. the light-independent reactions B. the light-dependent reactions C. coordination of protein synthesis D. coordination of hormone synthesis E. both C and D E. both C and D The fluidity of a lipid bilayer is enhanced with: A. decreased temperature. B. increased unsaturation in fatty acid tails. C. increased unsaturation in polar head groups. D. increased saturation in fatty acid tails. E. increased fatty acid chain length. B. increased unsaturation in fatty acid tails. An inbred strain of plants has a mean height of 24 cm. A second strain of the same species also has a mean height of 24 cm. When these plants are crossed, the F1 are also 24 cm in height. However, when the F1 plants are crossed, the F2 plants show a wide range of heights; the greatest number are similar to the P1 and F1, but approximately 4 of 1000 are only 12 cm tall and 4 of 1000 are 40 cm tall. What fraction of the F2 plants will be approximately 28 cm in height? [Assume that each of the alleles involved in determining increase in plant height contributes the same amount.] A. 314 B. 9/16 C. 56/256 D. None E. Cannot be determined from the information given. C. 56/256 The skin forming the flying surface in the wing of a bat and the feathers forming the flying surface in the wing of a bird: A. evolved from a similar structure in a common ancestor. B. are different because of adaptive radiation. C. do not develop from the same sources in the embryos of bat and bird, and are analogous. D. perform different functions in the bat and the bird. E. evolved in response to "felt need" in adult birds and bats. C. do not develop from the same sources in the embryos of bat and bird, and are analogous. Your parents built a tree house for you when you were 8 years old and 4 feet tall. They placed the tree house on a branch of a tree that was 5 feet above the ground in a tree that was 20 feet tall. You are now 17 years old and 6 feet tall. The tree has grown to be 50 feet tall. How high above the ground is the branch on which the tree house is resting now? A. 4 feet B. 5 feet C. 17 feet D. 20 feet E. 35 fee B. 5 feet When they encounter a predator, small fish form schools that look like balls, thereby: A. avoiding the predator. B. attracting less attention. C. looking like another predator. D. escaping more rapidly. E. confusing the predator; it is difficult to pick on a single fish. E. confusing the predator; it is difficult to pick on a single fish. The inspiratory phase of mammal respiration is characterized by: A. expansion of the rib cage and contraction of the diaphragm. B. expansion of the rib cage and relaxation of the diaphragm. C. collapse of the rib cage and contraction of the diaphragm. D. collapse of the rib cage and relaxation of the diaphragm. E. contraction and relaxation of the diaphragm. A. expansion of the rib cage and contraction of the diaphragm. To be functional, a linear chromosome most often contains at least: A. two telomeres, two centromeres, and a large number of origins of replication. B. two centromeres and an origin of replication. C. one centromere and an origin of replication. D. two telomeres and an origin of replication. E. two telomeres, one centromere, and a large number of origins of replication. E. two telomeres, one centromere, and a large number of origins of replication. In one form of Muscular Dystrophy, a sex-linked allele is the cause of the disorder. In this recessive form of the disorder the victims are almost invariably boys, who usually die before puberty. Why is this disorder almost never encountered in girls? A. Sex-linked allele cannot be inherited from mother to daughter. B. Nondisjunction does not occur in females, but does so in males. C. Sex-linked traits are never seen in girls. D. Males with the allele tend not to live long enough to reproduce. E. The Y chromosome is the site of the allele. D. Males with the allele tend not to live long enough to reproduce. Which of the following subdivisions of the autonomic nervous system would be most important to a zebra when it is fleeing from a lion? A. The enteric nervous system B. The parasympathetic nervous system C. Both the parasympathetic and enteric nervous systems D. The sympathetic nervous system E. The somatic nervous system D. The sympathetic nervous system