A man inherits dominant allele for the trait from father and recessive allele from mother. what trait will this man expressed which alleles will his sperm cell contain??

Explanation:

The dominant trait, since he has a dominant and a recessive allele.

Sperm cells are haploid, meaning contains only one of the two alleles available, in a random fashion.  Therefore on the average, half of his gametes (sperm cells) will have the dominant allele, and the other half will have the recessive allele.