Some heterozygous alleles create variations in expression so that there is not a clear dominant or recessive allele true or false?

Answer: False

The variations in expression depends on how genes code for proteins that would specify whether it will be dominant or recessive allele. Within a population, there may be a number of alleles for a given gene and these differences can cause variations in the protein that is produced. The change in protein expression affect traits due to the variations in protein activity or expression that produce different phenotypes.

Moreover, individuals that have copies of different alleles are known as heterozygous and individuals that have two copies of the same allele are referred to a homozygous. The expression patterns observed in inheritance will depend on whether the allele is found on an autosomal chromosome or a sex chromosome, and on whether the allele is dominant or recessive.