Question

which statement best describes an understanding of genetics that would be missing without the work of mendel?\
the dna codes for traits would not be known.\
the protein codes for traits would not be known.\
some alleles are dominant, and some alleles are recessive.\
offspring receive two copies of each allele from each parent.

Explanation:

Mendel's work established the concepts of dominant and recessive alleles (through his experiments with pea plants, showing how traits are inherited with some alleles masking others). Without his work, the understanding that some alleles are dominant and some are recessive would be missing. The other options relate to later molecular biology discoveries (DNA/protein coding) or basic inheritance of alleles (which is more about the law of segregation, but the key concept of dominance/recessiveness is directly from Mendel's work).

Answer:

Some alleles are dominant, and some alleles are recessive.