GMAT Critical Reasoning (CR) | A recent study has revealed, through meticulous research, a link

A recent study has revealed , through meticulous research,a link between the harmful hydrocarbons in air pollutants and the IQ test scores of children . The research involved measuring the quality of air that pregnant women breathed during the third trimester of pregnancy, and then following the children born from that pregnancy until an IQ test could be administered.Many external factors were taken into consideration , such as the mother's IQ and the family's home environment with regards to intellectual