Which disorder is determined by achievement test results that are substantially below what is expected for the child’s age, schooling, and intellectual ability?

Specific learning disorder

Explanation:

Specific learning disorder is that disorder in which a child is unable to perform average in some tests like reading, writing, and math-related test in the school. It is seen in these child that they have average intelligence but still they face problems in acquiring average intellectual ability and other educational skills.  

This disorder can be passed from parent to their children which mean it can be genetic. It can also occur during complications during the birth like lack of oxygen to the baby's brain. So the right answer is- specific learning disorder.

b) the heart is a pump made of muscle and that is difficult to grow in the lab.