ecologist are concerned about the accumulation of harmful chemicals are positions on predators such as the Barn Owl. DDT, PCBs, organophosphate pesticides, and heavy metals such as mercury are some of these chemicals. Why do you think predatory animals like owls are often threatened in habitats that have been exposed to these chemicals?

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides

cell division is not regulated in tumor cells.

i got you i did it ya know what it is just needing to fill this in for a quick task!