History of the Americas 235 human 225 Humans 203 female 181 male 167 Female 146 adult 143 Male 134 African American 127 Adult 106 Politics & government 96 African Americans 81 controlled study 77 Hispanic 76 Article 75 major clinical study 75 middle aged 72 psychology 72 adolescent 71 Adolescent 67 Middle Aged 67 United States 67 young adult 63 ethnology 61 Young Adult 58 Hispanic Americans 51 Caucasian 48 Literature: history & criticism 48 article 48 child 48