Hair color, eye color, and height are all examples of homogenic characteristics

What is a disadvantage of longitudinal research?

a. People are likely to drop out, so the sample size can be greatly reduced. b. It is relatively cheap, so other researchers don't take it seriously. c. Over time, more people want to join the study and there often end up being too many participants. d. With so much data, it is difficult to see trends over time within participants.

Atika's trunk and arms grow faster than his hands and fingers. This progression of motor development is called the __________________

a. cephalocaudal principle b. phalange-metatarsal principle c. dynamic movement principle d. proximodistal principle