Final answer:
The graduate student's research focus on biological, psychological, cognitive, and social changes over time aligns with the field of D. developmental psychology.
Step-by-step explanation:
A graduate student designing a research project to investigate the biological, psychological, cognitive, and social changes students experience over time is focusing on developmental psychology. This field studies development across a lifespan, considering physical maturation, cognitive skills, moral reasoning, social behavior, and other psychological attributes. Given the student's interests in how individuals change from conception through various life stages in multiple domains, including physical, cognitive, and psychosocial development, developmental psychology is indeed the area that aligns with her research focus.
The graduate student's focus can be classified as developmental psychology.
Developmental psychology is the scientific study of human development across the lifespan. It examines the biological, psychological, cognitive, and social changes that individuals experience over time. In this case, the graduate student wants to design a research project that explores these changes in students. Therefore, her focus would be classified as developmental psychology.