How are isotopos defined?
forms of different elements that have the same number of neutrons in each atom
forms of different elements that have the same number of protons in each atom
forms of the same element that differ in the number of neutrons in each atom
forms of the same element that differ in the number of protons in each atom

2. you__turn left on a red light if you are in the left-most lane of a one-way street, you're turning into the left-most lane of a one-way street, and no nearby sign prohibits the turn.

How do scientists think that gravity affected the formation of our solar system?

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