Although evolution has shaped human infant crying and the corresponding response from caregivers, there is
marked variation in paternal involvement and caretaking behavior, highlighting the importance of understanding the neurobiology supporting optimal paternal responses to cries.
A team of researchers has found
a marked variation among countries in contributions to the conservation of world's large mammal population, with poorer countries taking a more active approach than their richer counterparts.
Marked variations are exhibited with Asperger's depending on factors such as the form, severity, the level of early intervention, support, experience and continuity of the teacher and the acceptance, support and level of consistent loving handling.
These marked variations in the manifestation of liver disease (or phenotype) may be genetically determined or may be a result of environmental effects such as stress.