Answer:
Global temperatures; in the past half-century.
Explanation:
The graph of the global temperatures in the northern hemisphere was more or less costant until it spiked very hard in the past half-century. Therefore, it is called the "hockey stick" chart because its shape resembles a hockey stick. The original graph was made, as the exercise details, by Michael Mann and his colleagues in 1999.
Explanation:

<em><u>Bitcoin is a digital currency which operates free of any central control or the oversight of banks or governments. Instead it relies on peer-to-peer software and cryptography. A public ledger records all bitcoin transactions and copies are held on servers around the world</u></em>
Answer:
c is the right answer schizophrenia
Explanation: