Use my own simple English they will think I have use al

Here are the answers in simple English, as you asked:

1.4. Substance abuse can really harm young people's bodies. It can damage important organs like the liver (from too much alcohol) or lungs (from smoking). It also makes their immune system weak, so they get sick easily. Plus, they might not eat well, leading to malnutrition.

1.5. Drug abuse can mess up a young person's future career in two main ways. First, it can cause them to do badly in school or even drop out, making it hard to get the right qualifications for jobs. Second, it can lead to unemployment or losing jobs because it affects their thinking, makes them unreliable, and causes problems with working with other people.