Stewart, who is 2 years old, recently suffered a brain injury which resulted in him losing the ability to comprehend language. given what we know about brain plasticity and age, we might assume

We might assume that, due to injury stewart's brain functional part are lost. Brain plasticity are the ability of the brain to change the thoughts and thinking ability throughout life. It basically depend upon one's capability of thinking and their age.

Brain injury damaged the mental functions which resulting loss of brain disabilities life long. It also affect our life in many ways caused headache, memory problems and depression.  

i believe the answer would be negative peer pressure

i think the answer is d.