Answer: The given statement is False.
Heterozygous genes corresponds to the presence of different alleles for a particular trait ( such as Tt for plant height is a heterozygous condition).
This condition will not always display dominant trait ( trait that mask the expression of recessive allele).
For instance, the case of codominance exist when both the alleles in a heterozygous condition have independent effect in the phenotype. This can be explained through AB blood group, which is a codominant trait. An individual inherits A allele from one parent and B allele from another parent that represents AB blood group in the individual.
Similarly, incomplete dominance also exist when heterozygous condition represents an intermediate phenotype ( neither dominant nor recessive). For example- Formation of pink snapdragon ( Rr) from pure red (RR) and white flower (rr).