One kind of fish, the hagfish, is considered an invertebrate by scientists. why is this fish an invertebrate whereas all other fish are vertebrates?

The movement of tectonic plates in two different locations is shown below: two blocks labeled location a and location b are shown. at location a the top layer of the block shows two horizontal arrows pointing towards each other. small dunes are shown in the middle between the two arrows. the block labeled b has a vertical line in the middle. on the left of the line there is an arrow pointing down. on the right of the vertical line there is an arrow pointing up which statement is most likely true? subduction may occur in both locations. earthquakes may occur in both locations. subduction may occur in location a only and a volcanic eruption may occur in location b only. an earthquake may occur in location a only and a volcanic eruption may occur in location b only.

Coquina, a type of limestone, forms from shell fragments that settle on the ocean floor. what type of rock is coquina?

What best explains the inability for life to exist in earth early atmosphere