Answer:
D. A group of objects and materials that are interrelated
The disorder that he might be at risk of experiencing schizophrenia. This is a mental disorder which usually appears in late adolescence or early adulthood. Normally characterized by hallucinations, delusions, and other cognitive difficulties. This condition affects how a person thinks, feels and behaves, although not common as compared to other disorders it can be very disabling and a lifelong struggle.
Trees help the environment, they make oxygen from carbon dioxide. We should plant more because we are constantly chopping down trees to get wood, and planting more helps to ensure that will we will have trees in the future.
