USABO Open 2026 exam with
comprehensive questions and well
elaborated correct answers GRADED
A+
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,The production of the genetically engineered "golden rice" could be important to the people of
developing nations, especially in South-East Asia, because:
A. people are more likely to consume yellow grains than white
B. golden rice is less expensive to grow and harvest than white rice
C. golden rice is resistant to most commercially available herbicides
D. golden rice contains higher concentrations of β-carotene than white rice
E. golden rice has been engineered to produce biodegradable plastics - correct ans:D. golden rice
contains higher concentrations of β-carotene than white rice
A large population of laboratory rats was allowed to breed randomly for a number of generations. In this
population, a dominant allele at the A locus codes for agouti fur (A), and a recessive allele codes for
black fur (a). At the beginning of the breeding cycles, 49% of the rats had black fur. At the end of the
breeding cycles, this percentage was the same. The rest of the animals had agouti fur with
heterozygotes indistinguishable from homozygous dominants. What percentage of this population is
probably heterozygous for the fur color trait assuming the rats are following Hardy-Weinberg population
genetics?
A. 7%
B. 30%
C. 42%
D. 49%
E. 70% - correct ans:C. 42%
In Pompe's disease, the liver is damaged due to the accumulation of glycogen. What organelle is most
likely malfunctioning?
A. endoplasmic reticulum
B. golgi apparatus
C. lysosome
D. nucleus
E. vacuole - correct ans:C. lysosome
, Transport of which nutrient across the intestinal epithelium is by passive diffusion?
A. alanine
B. fructose
C. glucose
D. glutamine
E. all of the above - correct ans:B. fructose
Which two brain centers control mammalian respiration?
A. medulla oblongata and substantia nigra
B. medulla oblongata and pons
C. medulla oblongata and red nucleus
D. substantia nigra and red nucleus
E. red nucleus and pons - correct ans:B. medulla oblongata and pons
The presence of a vertebral column is with respect to all vertebrates [first term], but is with respect to
all chordates [second term].
A. analogous; homologous
B. analogous; derived
C. derived; primitive
D. homologous; analogous
E. primitive; derived - correct ans:E. primitive; derived
The main explanation for the lack of a continuing abiotic origin of life on Earth today is that:
A. there are no molten surfaces on which weak solutions of organic molecules could polymerize
comprehensive questions and well
elaborated correct answers GRADED
A+
Professional Academic Assistance Services
Services Offered
Proctored Exam Assistance
Online Class Management (Full Course Support)
Exam Preparation & Study Materials
Assignments and Coursework Support
Essays and Research Papers
Discussion Posts and Replies
n
,The production of the genetically engineered "golden rice" could be important to the people of
developing nations, especially in South-East Asia, because:
A. people are more likely to consume yellow grains than white
B. golden rice is less expensive to grow and harvest than white rice
C. golden rice is resistant to most commercially available herbicides
D. golden rice contains higher concentrations of β-carotene than white rice
E. golden rice has been engineered to produce biodegradable plastics - correct ans:D. golden rice
contains higher concentrations of β-carotene than white rice
A large population of laboratory rats was allowed to breed randomly for a number of generations. In this
population, a dominant allele at the A locus codes for agouti fur (A), and a recessive allele codes for
black fur (a). At the beginning of the breeding cycles, 49% of the rats had black fur. At the end of the
breeding cycles, this percentage was the same. The rest of the animals had agouti fur with
heterozygotes indistinguishable from homozygous dominants. What percentage of this population is
probably heterozygous for the fur color trait assuming the rats are following Hardy-Weinberg population
genetics?
A. 7%
B. 30%
C. 42%
D. 49%
E. 70% - correct ans:C. 42%
In Pompe's disease, the liver is damaged due to the accumulation of glycogen. What organelle is most
likely malfunctioning?
A. endoplasmic reticulum
B. golgi apparatus
C. lysosome
D. nucleus
E. vacuole - correct ans:C. lysosome
, Transport of which nutrient across the intestinal epithelium is by passive diffusion?
A. alanine
B. fructose
C. glucose
D. glutamine
E. all of the above - correct ans:B. fructose
Which two brain centers control mammalian respiration?
A. medulla oblongata and substantia nigra
B. medulla oblongata and pons
C. medulla oblongata and red nucleus
D. substantia nigra and red nucleus
E. red nucleus and pons - correct ans:B. medulla oblongata and pons
The presence of a vertebral column is with respect to all vertebrates [first term], but is with respect to
all chordates [second term].
A. analogous; homologous
B. analogous; derived
C. derived; primitive
D. homologous; analogous
E. primitive; derived - correct ans:E. primitive; derived
The main explanation for the lack of a continuing abiotic origin of life on Earth today is that:
A. there are no molten surfaces on which weak solutions of organic molecules could polymerize
