​Cosella is conducting an experiment where she assesses how quickly teenagers can run a 100-meter race after consuming specific amounts of caffeine. She divides her sample up into three groups. Group 1 receives a glass of water with no caffeine added. Group 2 receives a glass of water with an amount of caffeine equivalent to that in one cup of coffee. Group 3 receives a glass of water with an amount of caffeine equivalent to that in two cups of coffee. Each participant is then timed as they run the course. In this study, the independent variable is

​The major risks of a mother contracting the chicken pox during pregnancy include encephalitis, an enlarged spleen, and blood clotting problems in the baby.

​The ecological theory of Urie Bronfenbrenner proposes that there are three interacting levels of environmental context that influence human development.

Recent advances in the synthesis of artificial formula have resulted in experts agreeing that breastfeeding and bottle-feeding a baby are equally beneficially to the child.

​Why is it that an orienting response tends to disappear after repeated exposure to a stimulus?

​What is the primary thrust of the psychosocial theory of development?

The Apgar score is calculated by assessing 7 vital areas of functioning in a newborn on a scale of 1 to 3 points. A higher the score indicates a healthier baby.

Scott understands that when he counts his toy cars, there is one and only one number for each separate car. This demonstrates that Scott has mastered the principle of cardinality.

​The continuity-discontinuity issue concerns whether there is just one path of development or several.

​Piaget’s theory is often criticized for having overestimated the cognitive skills of infants and young children and for underestimating the cognitive skills of adolescents.