The most extreme symptom of cardiovascular disease is

Which of the following are characteristics of REM sleep?

flickering of the open eyes and rapid brain waves flickering of the closed eyes and rapid brain waves flickering of the open eyes and slow, steady brain waves flickering of the closed eyes and slow, steady brain waves

Toddlers who are friends

a. tend to be complementary in their activity levels, interaction styles, and social skills, much like siblings of different ages b. prefer playing with a same-sex peer as early as 30 months of age c. change their choices of playmates frequently (friendship is unstable before the age of three) d. often have their friendship overlooked by parents and teachers because their friendship looks different from the friendship of older peers