Maria's genotype is XeXE. What do you know about Maria and whether or not she expresses the trait carried by Xe?

From the XEXe genotype, we can deduce that Maria is heterozygous for this gene, given that she has two different alleles (E and e).

The allele e does not express itself in Maria because it is recessive (it is in miniscule). It is expressed only in case of homozygosity for this allele. Maria will express the E allele by the principle of the dominance of the alleles.