Two Traits at Once

40 questions on this block. Tap an answer and it moves on by itself — correct answers advance immediately, misses hold a few seconds so you can read why.

Where 9 : 3 : 3 : 1 actually comes from Do each trait on its own, then multiply. 3/4 and 1/4, multiplied four ways. It is not a number to memorise.

Warm-up · not scored

Click the buttons and watch what changes.

R = round, r = wrinkled. Y = yellow, y = green. Each gamete gets one allele of each gene, so each parent makes up to four kinds of gametes.

Part 1Two traits do not interact

Part 2Gametes from a two-trait parent

Part 3The product rule

Part 4The 16-square

Part 5One trait on a two-trait square

Part 6Reporting the answer and mixed practice

Two Traits at Once

Warm-up · not scored

Review Complete

Worth another look