Cassandra and her mother have been playing patty-cake, but her mother is now trying to engage Cassandra in a picture book. Cassandra wants to play patty-cake again, so she grabs her mother's hands and puts them together as if in a clap. Cassandra is clearly in stage of sensorimotor development.

What is one main reason some governments in the twentieth century began campaigns of genocide? a) a minority group wanted total independence. b) a minority group wanted more say in lawmaking. c) a minority group had different cultural customs. d)a minority group protested against government policy.