I wasted my time, pls help me with this again

What property is a characteristic of a substance that can be observed and does not change the identity of the substance

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length (in m) of a column of water 1.45 km high for a temperature increase of 1.12°c. assume the column is not free to expand sideways. as a model of the ocean, that is a reasonable approximation, as only parts of the ocean very close to