2.1.1 ) Homologous pairs 2.1.2) 45 2.1.3) Gonosomes 2.1.4) The presence of a Y chromosome 2.1.5) chromosom mutation 2.1.6) Non disjunction occurred at position 21 during anaphase resulting in one gamete with 24 chromosomes. The fertilisation of this gamete with a normal gamete results in a zygote with 47 chromosomes. There are 3 chromosomes.
