Is "diamonds are the hardest known substance" a physical property?

Which set of characteristics best describes igneous rock? a) largest type of rock, made of organic matter, hardest type of rock b) least abundant type of rock, made of other rocks, made mostly of minerals c) found on all continents, contains wavy bands of stripes, contains fossils d) most abundant type in earth's crust, made of magma/lava, contains no fossils

How are isotopes of the same chemical element alike? how are they different?

According to the tide table below what time of day will the highest tide occur? (2 pt) the highest tide will occur at