For the first question:
Bacteria and humans are similar in that they grow and reproduce.
For the second question:
If the temperature in Prudhoe Bay, Alaska is −2°C and the temperature in Kirkenes, Norway is 6°C warmer, you would add 6°C to −2°C:
-2°C + 6°C = 4°C
So, the temperature in the Arctic Ocean of Kirkenes, Norway is 4°C.