What proportion of the population is probably heterozygous (aa) for this trait?.

How many questions do they give on the sat

What dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean what dose sat mean

The authors use the word “backbone” in lines 3 and 39 to indicate that