Monte: Withdraw cash slot machine for sale But the economy's slow recovery from the recession has been a difficult challenge for Obama, who in recent weeks has been focused largely on foreign policy in trying to mount an international response to a chemical weapons attack in Syria. home work help for kids They had 187 people smell 10 different compounds, taking note of who could smell them at a certain concentration level and who couldn't. They sequenced each person's DNA, scanning their genomes to pick out parts that could possibly explain the variations in smell sensitivity.