Robin can have a ddt concentration of 444ppm while the ddt concentration of soil is 10 ppm. This happens due to biological magnification.
<u>Explanation:</u>
In biological magnification the concentration of toxic substances at successive trophic levels keeps increasing. Due to biomagnification, what starts out as a small concentration grows while moving to successive trophic levels. DDT is a pesticide which is used to kill pests that affect crops.
DDT used in farms gets deposited in the soil. From the soil it can reach various trophic levels. At each trophic level its concentration keeps increasing.
Robin is a bird that is a secondary consumer and thus belongs to the higher trophic level. Thus even if the DDT concentration is as low as 10ppm in the soil its concentration will keep increasing and can become a high value like 444ppm.
It is not possible for Sarah and Thomas to develop cystic fibrosis but it would be possible for one of their children to inherit it. Both Sarah and Thomas are heterozygous and in a heterozygous pair of alleles the dominant allele is the one that will present. Because Sarah and Thomas both have the heterozygous allele combination Ff they are carriers which means that they will not experience symptoms of cystic fibrosis but they could pass cystic fibrosis onto one of their children.
