Brain development in infancy and toddlerhood is (A) often characterized by a series of discrete stages. (B) jointly influenced by genetically programmed events and the child's experiences. (C) slow and steady, and mostly influenced by genetically programmed events. (D) primarily influenced by the child's experiences with the environment.

Answer: B. Jointly influenced by genetically programmed events and the child's experiences.

Explanation: Brain development in infancy and toddlerhood is very important because the brain develops very quickly during this period. Although the brain does not cease to develop even at later ages and stages in life, this period of brain development, specifically up to eight years of the child's life, is the basis for later brain abilities. Scientists say that in addition to genetic predispositions, brain development is also influenced by a child's experiences with people from the environment, nutrition, and exposure to toxins such as smoke from cigarettes, etc. various infections that can lead to potential brain development problems. When it comes to nutrition and toxin exposure, this should be taken into account during pregnancy.