Question

a student recorded the height of each student in the school. she then made a bar graph of her results. she observed that the results form a bell - shaped curve. the student could use her graph as evidence to support which argument?
height is affected by multiple pairs of genes on different chromosomes.
the alleles for tall height and short height are codominant.
the allele for being tall is dominant to the allele for shorter heights.
there are three alleles for height that demonstrate incomplete dominance.

Explanation:

When height is affected by multiple pairs of genes (polygenic inheritance), it often results in a bell - shaped (normal) distribution of heights in a population. Codominance (where both alleles are expressed equally like in AB blood type) would not lead to a bell - shaped curve for height. Simple dominance (where one allele masks another) usually gives a more discrete distribution (e.g., either dominant - like phenotype or recessive - like phenotype in a simple Mendelian sense, not a continuous bell - shaped curve). Incomplete dominance (where heterozygotes have an intermediate phenotype) also does not typically produce a bell - shaped curve for a trait like height which has a wide range of values.

Answer:

Height is affected by multiple pairs of genes on different chromosomes.