В чем разница между "snorkeling" и "scuba diving"?

As I know snorkeling is a diving with air tank, but in "scuba diving" air tank is used as well. Thank you.

Snorkeling requires an air tube which extends from a person's mouth to above the surface of the water - which is the source of oxygen.

As you stated, scuba diving requires an air tank allowing the diver to go deep.

Snorkeling is done at the surface level with the head submerged below the water.

thank you very much, Patrick!

Hi Elena, snorkeling is a diving with a diving mask, snorkel and swimmfins without breathing apparatus.

Can anyone explain the difference between "backcountry skiing" and "crosscountry skiing"? Thank you in advance.

Irina, back-country skiing and cross-country skiing are almost identical (my opinion). I believe back-country skiing is a form of exploring the wilderness while staying a few nights in a tent located in a remote location. Where as cross-country skiing is done more for leisure and sport - not as intense.

I am not a skier, so I can only assume based on what I have read.

guys you're all clinical

Thank you, Patrick. I had a great deal of discussion about this subject with my german friend. She doesn´t see the difference between both kind of skiing like you. I don´t know for sure, but I think there must be a difference. I do know that back-country is an american term for special kind of skiing and in Europe it isn´t allowed because of lack of safeness (skiing in unmarked or unpatrolled areas) but I think the main difference between both is the using of different ski equipment – for back-country skiing you need alpin ski and for cross country the normal “cross-country ski”. This was my opinion. What a pity! I've lost a bet.

Ирина

back-country skiing requires adapted Alpine equipment, because this term usually refers to skiing on the back of the resort - skiing downhill, getting up without the lift and then skiing down.
cross-country skiing done almost on a flat terrain - anywhere, but does not really involve climbing up to ski down type skiing....
take it from the certified ski instructor ))