I don't know exactly what you mean but the size of a group affects its defense because there is a larger group. Therefore, more people would be protecting it, adding more to its defense.
The dominant ones. Whatever has been gained through evolution in adaptation to their specific environment.
... increase their chances of displaying this said attribute in higher incidence and frequency
The different degrees of sleep and wakefulness through which newborns cycle, ranging from deep sleep to great agitation, are called states of arousal. These states are regular sleep, irregular sleep, drowsiness, quiet alertness and crying. About eight to nine hours each of an infant's day is dedicated to regular and irregular sleep. So, most of the time of the infant is spent in these states. These are the states where the brain of an infant is developing the important connections for growth and survival. Crying is the means for infants to communicate their needs. Different type of cries would represent different needs of the infant.
