Yes
If you lay the coin face up, and turn it left to right, the reverse should be upside down. This is normal for all US coins.
All US coins use metal
There are different people on the coins. Not all are the same
All
Four words that appear on all US coins are "United States of America."
Because without coins the empires would not get bombs and all
"E Pluribus Unun" and "In God We Trust" are some sayings that are used on US coins. US coins no longer have to say "In God We Trust" but so far they all do.
No current circulating US coins contain any silver at all. For information about older coins, please see the Related Question.
ALL U.S. coins have the back side inverted with respect to the front.
The FACE value is the same as all other US coins set by the denomination.
No they don't all have mintmarks.
No, retailers are allowed to accept whatever in payment for goods, be that US coins, Chinese Coins, gold and silver coins, or toothbrushes. A retailer can refuse to honor some or all US coins. However, since US coins are legal tender, a company cannot sue you for not paying a bill previously agreed upon in US dollars for paying in US coins. But at the point of purchase, a retailer can demand payment in whatever and can refuse US coins.