| Date | November 2020 | Marks available | 1 | Reference code | 20N.1.HL.TZ0.35 |
| Level | Higher level | Paper | Paper 1 | Time zone | TZ0 / no time zone |
| Command term | Question number | 35 | Adapted from | N/A |
Question
Andalusian fowl have varied colours and types of feathers. The allele for black feathers is codominant with the allele for white, producing blue feathers in the heterozygote. The texture of feathers is controlled by another gene, with silky feathers recessive to normal. Blue silky birds are crossed with black silky birds. What is the expected proportion of blue silky offspring?
A. 0%
B. 25%
C. 50%
D. 100%
Markscheme
C
Examiners report
[N/A]
