Questions: A professor tells students, "In order to understand human development, you can't just study infants, children, or teenagers. You need to study people over the course of their entire lives." Which of Baltes' key principles of lifespan development is this professor supporting? Development has socio-cultural influences. Development is lifelong. Development has only gains. Development is changeable.

The answer is Development is lifelong.

This principle emphasizes the impact of social and cultural factors on development. While important, it does not directly address the professor's point about studying people over their entire lives.

This principle asserts that development occurs throughout the entire lifespan, from birth to old age. The professor's statement aligns with this principle, as they emphasize the importance of studying individuals at all stages of life to fully understand human development.

This principle is incorrect as it oversimplifies development. Development involves both gains and losses, and this option does not relate to the professor's emphasis on studying the entire lifespan.

This principle highlights the plasticity and potential for change in development. While relevant, it does not specifically address the need to study development across the entire lifespan as the professor's statement does.