Compared to the desert fennec you might expect the arctic fox to have

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.

you know they are heterozygous for a trait because they have it as jj or jj.