USABO OPEN EXAM 2025/26 QUESTIONS AND ANSWERS!!

USABO OPEN EXAM 2025/26
QUESTIONS AND ANSWERS!!




1 of 41

Term


In the fox, there are 9 coat colors: red, standard silver, Alaskan silver,
double-black, smoky red, cross-red, blended-cross, substandard
silver, and sub-Alaskan silver. A red fox was crossed with a double-
black fox and their offspring were then crossed with each other. The
F2 phenotypes were - 10 red : 18 smoky red : 20 cross-red : 39
blendedcross : 9 standard silver : 19 substandard silver : 12
Alaskan silver : 22 sub-Alaskan silver : 8 double-black. How many
genes are involved in this cross?


A. 18 genes
B.4 pairs of genes

, C. 9 genes
D.9 pairs of genes
E. 4 genes



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B. 13 white : 3 black A. Most likely 100%




B. 4 pairs of genes D. Compartment syndrome


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2 of 41

Term


Plant cells maintain their structural integrity partially by ________________ while
animal cells maintain structural integrity partially by
__________________.


A. turgor pressure, cholesterol.
B.high specific heat, cuticle.
C. cuticle, cholesterol.
D.cholesterol, turgor pressure.
E.tightly packed cells, loosely packed cells.



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