The abbreviation of the medical term referring to the result of decreased secretion of antidiuretic hormone by the posterior lobe of the pituitary gland causing polydipsia and polyuria is

In a population that is in hardy-weinberg equilibrium, there are two possible alleles for a certain gene, a and a. if the frequency of allele a is 0.4, what fraction of the population is heterozygous? a. 0.40 b. 0.60 c. 0.16 d. 0.48