Why do the left propeller on aircraft spin clockwise and the right engine spin counter clockwise?

Yes. Jet packs do exist.

From a pilot's point of view, every aircraft comes from the factory with a checklist of things to look at specifically before every flight to ensure airworthiness. It's generally called a walk-around inspection, checking flight controls for security and condition, tire condition, engine for obvious problems. propeller, fuel and oil quantities. and many other things. The walk around also includes checking to ensure all required paperwork is there including weight and balance, airworthiness certificate, aircraft registration, operator's manual. etc. I would also check the log book to verify the transponder check was done within the past 24 months and the annual or 100 hour inspection is current. From an A&P mechanic point of view much the same applies, however I would look much closer at the maintenance logs for engine and airframe.

Well technically you can make a ducted fan plane but it is highly inefficient as battery technology is still in its infant stages as well as batteries are still very heavy. Secondly Jet engines are basically high bypass turbines.. They can technically run on many different fuels such as diesel, kerosene, and propane.

Yes. There are propeller driven airliners in service today, mostly on short routes.

If you are flying level you climb. If it's a propeller plane and you don't add rudder to counter "P factor" you may also turn a bit.

here ya go...
http://www.explainthatstuff.com/jetengine.html
tis physics.

Hacksaw

The DC10 was an excellent aircraft, with a long and successful service history. They are still flying in many countries, and in the US you see lots of them with the freight haulers.
There were, unfortunately, a few (very few) high profile crashes - which is probably what you refer to. The infamous "engine drop" issue was bad maintenance - not a problem with the aircraft design. And the Sioux City crash (pilot Al Haynes) was caused by a truly unlikely event that simply proves that even low odds can happen. [An uncontained blade failure on the #2 engine ejected "just right" (or just wrong) and cut the one small spot where all the control surface hydraulic lines came briefly together.]
The reason that DC10's are no longer in primary service is attributable to two things:
1. Older fuel hungry engines (3 of them), compared to the more fuel efficient twin engine design. And the changes to ETOPS regulations that now allow twin engine airliners to fly trans-ocean.
2. Certification of the aircraft with a three-person crew, in stead of the cheaper two-person flight crew common now. [The freight haulers get around this by cross training the loadmaster (only needed on the ground) to also be the flight engineer (only needed in the air).

Aircraft too heavy. Weight is extremely valuable/expensive and the weight of a parachute system would be too heavy and costly, sacrificing room for paying passengers.