To identify the simple sentences, we need to find sentences that contain only one independent clause. Here are the simple sentences from the list:

1. She doesn't eat much red meat. (Simple)
2. I wash my face twice a day. (Simple)
3. I am hungry. (Simple)
4. He likes eating fish, but his brother doesn't like it. (Not Simple - Compound)
5. I like going camping in the forest. (Simple)
6. My mother cooks very well, and I also do it well. (Not Simple - Compound)
7. He has vegetables and eggs for lunch. (Simple)
8. My cousin works hard, and he does exercise regularly. (Not Simple - Compound)

So, the simple sentences are:

1. She doesn't eat much red meat. (Tick)
2. I wash my face twice a day. (Tick)
3. I am hungry. (Tick)
5. I like going camping in the forest. (Tick)
7. He has vegetables and eggs for lunch. (Tick)