Chimerism is what happens when cells from one twin are present in the other. For example, white blood cells with Y chromosomes would be found in the female twin.
: of, relating to, or involving conscious mental activities (such as thinking, understanding, learning, and remembering). cognitive development/psychology/impairment. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples.
Cognitive milestones refer to the child's developmental abilities to think, learn, and solve problems. A two-year-old being able to point at pictures in a book and give them the correct names and a four-year-old being able to do basic counting are examples of cognitive milestones. Third, there are social and emotional milestones.