Keep it simple past: "Who built the pyramids?" or "Who actually built the pyramids?" if you are interested in the actual laborers, and not the king or pharoah that they were built for.

Is there more to this sentence? It doesn't make sense. Is the original "That fact that he will act on it is good?" If so, than the root sentence is "fact is good," and "that he will act on it" tells us what the fact is.

Although older people often go to sleep much earlier, they also often get up quite early. Many feel sleepy about 9 pm but they actually don't need as many sleeping hours as a younger person. [I assume the next sentence is not about the elderly, and I assume that you are actually writing to specific people, not about them. If you are writing about the elderly still, don't switch to "you."] The most important key is that should go to bed before 12 pm: don't burn your midnight oil! In my experience, washing your feet in hot water may help you feel sleepier. It depends on how fatigued I am. I can sleep in a noisy restaurant if I haven't slept in 24 hours. However, in most situations, I will toss and turn, and can't fall in sleep in a noisy environment.

You're right, and submissive is usually an adjective, while pushover is a noun.

I wonder, when your patients talk to you, do they give as many details to you as you give to me when you talk to me.

"give in to" -- I don't want to argue with my wife anymore, so I give in to her. I give into temptation and eat the donut. "submit to" -- I submit this answer to you. I submit my paper to the teacher. Also, I submit myself to God. In a patriarchal structure, wives submit to their husbands and children submit to their parents. This is more profound than "give in to" -- it's more voluntary and permanent. "succumb to" -- He succombed to cancer or heart disease. [probably meaning he is dead] If I say I submitted to or succumbed to the donut, I'm being quite dramatic and denying that I had any power to resist.

When you join two independent clauses with "and," you need a comma before the "and" -- "... America's, and ..."

I like to figure skate. -- I do it. I like figure skating. -- I do it or I watch it. Figure skating is like dancing on ice. -- similarity Ice sports, like skating, are my favorite. -- skating is an example of the catagory. This is commonly done, but in professional or academic writing, "such as" or "including" would be better. "And I was like, 'get away from me! You are like so gross!'" -- American teenage slang that drives teachers like crazy.