Read the following paragraph and write the topic sentence on the answer sheet.
The argument over whether intelligence is innate or environmentally influenced has been going on for more than a century.One of the most recent issues in the“nature versus nurture”(先天对后天)debate is the effect of breast-feeding on IQ.Research shows that the fatty acids(酸)in human milk may influence brain development.Using that data as a starting point, a group of scientists, led by a team at the King's College London Institute of Psychiatry,set out to determine how the make-up of infants interacts with their mothers' milk to affect intelligence.Their finding is that breastfeeding can boost a baby's IQ if the newborn has a certain version of a gene, called FADS2,which affects how fatty acids are processed.