they has different pronounciation. "ㄱ", called "Gi Yeok" is used to pronounciate "G" and "ㅋ", called "Ki Yeok" is used to pronounciate "K" for an example, "Go" is wrote "고" with "ㄱ" in korean. one thing you have to keep in mind is that "Gi" doesn't read "zi" in korean. In korean, you have to read it with ㄱ. and "Ko" is wrote "코" with "ㅋ" in korean. and also korean netizens use "ㅋ" to express their laughing. "ㅋㅋㅋ" means LOL in english. in this use, "ㅋ" comes from sound of laughter like "KiKiKiKi"

I think global warming is not a problem. it's just a process of nature. this planet is going step by step to make a big change like iceage. the real prolem that we are facing now is the contamination. becoming warmer is just a process so it is natural but contamination is not. it's make the earth ill. that's not natural.

I can answer without hesitation.
MONEY!
If I have enough money, it will attract both career and love.
It's cold but true.

쿵짝 is onomatopoeia word. It can be used seperately. 쿵 is kinda big and heavy sound like big giant's walking or instruments sound like a trombone. 짝 is sound of a clap or slap on the face. but if you heard this in the song, it could be used for beating time. 쿵짝 sounds cheerful and lively.