Question

The allele which expresses itself only in the presence of another similar allele

Answer 1

The dominant allele influences the outward appearance of plants in the filial generation.Homozygous recessive: Both the alleles arerecessive and expressed as 'tt'. Therecessive allele can express itself only in the presence of another identical recessiveallele.

Answer 2

The answer is recessive allele as it is expressed only when they are in similar pairs(homozygous recessive).