Steemit dollar and Bitcoin: What i need to know

Am so curious about this two powers
What is a bitcoin?
What is a steem dollar?
How do they work?
What's the future prospect?
Is it worth dying for?
Cryptocurrency stuff on my mind
Help a friend
Thanks

Coin Marketplace

STEEM 0.15
TRX 0.12
JST 0.025
BTC 53406.14
ETH 2398.08
USDT 1.00
SBD 2.15