Answer:
A graph not only depends on the data that we are graphing, there are other important factors such as the units we use (here we have °C vs years, but we could have °F vs days and we would see a different graph, which represents the exact same information) , the scale we use (a lot of graphs are misleading because of the use of logarithmic scales, we need to be clear about the scales we use), where we put the zero of each axis (We usually use the intersection of both axes as the (0, 0) point, but this is not a necessary condition, we could manipulate our coordinate axis as we want) , etc.
So there are a lot of things that can impact on how we see the graph of the same data.
About the second answer, one could interpret from that graph that the actual temperature between the years 1880 and 2020 was around 14°C.
