Answer to this question ?

Answer:
[tex]\Large \boxed{\sf 50\%}[/tex]
Explanation:
[tex]X=Aa[/tex]
[tex]Z=bb[/tex]
Heterozygous is when an individual has two different alleles of a gene.
[tex]Heterozygous \rightarrow Aa,Aa,Bb,Bb[/tex]
[tex]\displaystyle \frac{no. \ of \ heterozygous}{total \ no.}=\frac{4}{8} =0.5[/tex]