Biology questions and solutions

Browse original practice and official past-paper questions. Each question has its own link, with its source and worked solution.

385 questions · Page 17 of 17

1. Q155 · Original practice · 9 marks
   A flowering-plant population initially contains 20 RR, 20 Rr and 10 rr plants. A flood kills plants independently of genotype. Only two Rr and two rr plants survive. Genomic profiles also show loss of several rare alleles at other loci. A nursery makes 3000 rooted cuttings from each survivor, producing 12 000 plants; no mutation occurs and all clones are equ…
   Continuity of life on Earth