What factor most likely motivated early Americans to migrate across north and south america

Aresearcher is studying women recently admitted to a state prison. all potential subjects must have children under the age of five. research subjects will be given a basket of toys to use at their children’s first visit that the children can then take home. in assessing this proposal, the irb needs to determine that the toys are: age appropriate.not an excessive incentive.educational.of high quality.