Join TSR now and get all your revision questions answeredSign up now
    • Thread Starter

    I'm pretty confused by Q2 b(iii) from this paper

    I put homozygous black as the answer (i.e. BR BR), however, this is incorrect and I can't see why.

    This is from the examiner's report:

    "‘Homozygous black’ was a popular incorrect answer but although these will always give black pups the genotype cannot be guaranteed from the phenotype."

    Why can't the genotype be proved? Surely if BR BR is crossed with BR BR, all the pups will also be BR BR?

    Thanks for any help
If you won £30,000, which of these would you spend it on?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.