Production of pcbs was discontinued in 1977, yet pcbs are still found in the environment. the reason for this is pcbs are very reactive molecules. pcbs are very stable molecules. pcbs are imported from other countries where their production is not banned. pcbs are formed naturally by plants

PCBs are very stable molecules

Explanation:

PCBs are approximately 209 compounds made of chlorine. PCBs are formed  synthetically.These compounds have high chemical and thermal stability so their chemical and biological physical degradation is very slow.

The years that these compounds can last are 2 weeks to 2 years in water, 6 years in the soil, and more than 10 years in fish.

italy's population growth rate is almost at zero, the national statistics agency, istat, said on monday, mainly due to a dwindling birth rate.

small, big, or no change could occur in the phenotype. it could cause something as simple as a cats ears to curl backwards or something as frighting as death. it could also occur in the protien-coding area and have an effect on that but no effect on the amino acids. what has to occur is a changing in the hox gene or the control gene.