Johann lives in a family with five siblings. There is always a lot of activity and interaction between the children and parents, and there are many brightly colored toys to play with. Suzanne's family can't afford many toys, and she only has old hand-me-downs to play with, most of which are broken. Which of the following best describes a likely difference in brain development between Johann and Suzanne?
◦ The "use it or lose it" principle would indicate that because Johann is in a more stimulating environment than Suzanne, his brain will have a denser network of neurons and synapses.
◦ Johann's neurons will myelinate more quickly and completely than Suzanne's.
◦ Because Johann and Suzanne are both under two years of age, the differences in environment will have little impact on their continuing development.
◦ The principle of synaptic pruning indicates that because Johann is in a more stimulating environment than Suzanne, his brain will have a smaller number of synapses.
The family tree of HIV and related viruses
A signature sequence in the EF-1α/EF-Tu protein family
Vienna: Social Structure and Social Interaction
Example of a family genogram with accompanying legend (symbols used in genograms).
Peer group activity of adolescents
Penicillin saved the lives of many soldiers in World War II