To help you answer your own question (we'll help you with it, but we won't do your homework for you....)
What have you already learned about SCADA and PLCs? (I.e. if this is for homework, you will already have discussed this material in class or it was discussed in your text book......)
What does "SCADA" stand for? How is it implemented or realized? What is required for a SCADA?
What does "PLC" stand for? Can PLCs be networked? Why/Why not? Are there non-networked PLCs? Benefits/applications of both???
Based on these definitions, is a SCADA a PLC? If not, why not? Can a PLC be a SCADA? Why/Why not?
Thought patterns like this are required for being a good programmer, too! You'll have to learn to think through things logically. It's not uncommon to have to program a system that you know absolutely nothing about, so you have to ask these types of questions to succeed!
The hardest part of any automation project - and the most important part - is defining WHAT you want to do. Whether that's a flow chart or a process narrative or whatever, you have to answer the questions. You need to know what triggers the next step, how you know something is ready to happen. Then how you know it's done happening. And what to do if it failed to happen.
Learn to think this way when you're programming. And apply it to your homework. Then you'll succeed in both your education and your career.