What this suggest about rounded wings?

The round wings of fruit flies is dominant over the curled type.

Explanation:

A dominant trait can be described as a trait which is determined by the dominant alleles. The dominant alleles have the tendency to mask the effect of the recessive trait. Hence, a dominant trait can either be homozygous or heterozygous for the trait.

A recessive trait gets suppressed y the dominant trait. For a recessive trait to occur, both the alleles of the gene should be recessive for that trait.