1) the age at which children understand abstract concepts
2) how conflict affects marital happiness
3) brain development during adolescence
4) which psychological test would best predict job success

3

Explanation:

The full question goes like this

A neuroscientist would be most likely to study which of the following topics?

) The age at which children understand abstract concepts 

2) how conflict affects marital happiness 

3) brain development during adolescence 

4) which psychological test would best predict job success

The reason why is because his area of speciality is the brain thats is what a neurologist does, the rest are not directly associated with the profession. Neuroscientists focus on the brain and its impact on behavior and cognitive functions. 

answer; for children with two myopic parents,the likelihood of becoming myopic is ) correlated with the number of hours spent playing sports each week;

thomas jefferson

explanation: