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UAT-UK SPEC: B4MODULE: BIOLOGYTOPIC ID: ARCH-B-05

Non-Mendelian Ratios (2:1 Lethal Alleles, Codominance, Dihybrid & Multi-Cross Phenotypic Ratio Tables)

Master Non-Mendelian Ratios (2:1 Lethal Alleles, Codominance, Dihybrid & Multi-Cross Phenotypic Ratio Tables) on the ESAT Biology paper. Traditional classroom derivations waste valuable seconds. Using the 2-step Sub-90 invariant elimination method compresses solve time to 35s, saving +95s per question.

Standard Classroom Time
130s
Textbook multi-line derivations bleed exam clock
Sub-90 Target Pace
35s
Comfortably below the 88.8s per-question limit
Time Saved for Review
+95s
Banks clock buffer across 27 questions

2-Step Sub-90 Shortcut Formula

How to eliminate intermediate algebra and solve under 45 seconds.

Launch Interactive Lesson
STEP 1 • SETUP INVARIANT (LINE 1)10–15s
Line 1 (Lethal 2:12:1 Signature): Yy×Yy→YY,Yy,yY,yyYy \times Yy \to \cancel{YY}, Yy, yY, yy (33 survive).

Establish the structural invariant and eliminate impossible options immediately.

STEP 2 • FAST SOLVE (LINE 2)15–25s
Line 2 (Live Fraction): 2 yellow (Yy)3 live=23\frac{2\text{ yellow }(Yy)}{3\text{ live}} = \frac{2}{3} (20s).

Evaluate the simplified expression using integer factoring or unit elimination.

Distractor Trap Forensics

The predictable cognitive traps engineered by examiners into the wrong options.

TRAP #1sign_or_direction_flip

Swapping red blood cell surface antigens with plasma antibodies (e.g. saying Group A has anti-A antibodies)

Group A has A-antigens on RBCs and anti-B antibodies in plasma (having anti-A would agglutinate its own blood!).

Sub-90 Fix: Test invariants before expanding equations.
TRAP #2fence_post_or_domain_trap

Assuming Group A x Group B parents can only produce A, B, or AB offspring (forgetting Iᴬ Iᴼ x Iᴮ Iᴼ -> 1/4 Iᴼ Iᴼ Group O)

Assuming homozygous Iᴬ Iᴬ instead of heterozygous Iᴬ Iᴼ.

Sub-90 Fix: Test invariants before expanding equations.
TRAP #3sign_or_direction_flip

Reversing universal donor (Group O: no A/B antigens on RBCs) and universal recipient (Group AB: no anti-A/anti-B antibodies in plasma)

Matching donor antibodies against recipient cells instead of donor RBC antigens against recipient plasma antibodies.

Sub-90 Fix: Test invariants before expanding equations.

Try 1 Timed Question: Non-Mendelian Ratios (2:1 Lethal Alleles, Codominance, Dihybrid & Multi-Cross Phenotypic Ratio Tables)

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Full Lesson All 15 Questions (ARCH-B-05)
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ARCH-B-05: Non-Mendelian Ratios (2:1 Lethal Alleles, Codominance, Dihybrid & Multi-Cross Phenotypic Ratio Tables) (Sample)Biology
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SUB-90 ZONE (<50S)
0.0s50s Sub-9090s ESAT Budget150s Classroom
Question 1 of 1ARCH-B-05 (6-Card Lesson)Format: Table-Row Matching
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Question 1 of 1 • 90s Target

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