Genotype for heterozygous for A allele

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.