You could write this essay in a couple different ways. The point is to take an argumentative stance and then provide research for your stance.
These are some ways you could go, based on your opinion:
a) that subliminal messages are picked up by our senses, meaning they are real and do affect behavior
b) that subliminal messages are not picked up by our senses and do not affect behavior
If you're not sure which stance to take, just do some general googling of subliminal messages and whether they're real & affect behavior.
Once you find your position, start researching specifically for that. Remember that this is argumentative- you're taking a position- so you want to have real facts as support. Use reputable sites (look for .edu, .org, .gov instead of .com).
Craft your thesis, which is the main claim you're making. This will go in the introduction of your essay.
A basic thesis may go like:
Subliminal messages are/are not real, and they have/do not have an effect on behavior. (You would pick between belief or nonbelief).
Once you have your thesis, you can start organizing your information around it and write the essay!
Answer:
What text I will edit my answer when I know what text and so you can give it to me.
Explanation:
I am not sure but maybe he wanted to make things suspenseful and make new problems and conflict
