After a volcanic eruption, lava flowed over an area and then cooled to form a thick layer of new rock. One thousand years later, a thriving forest with diverse flora and fauna is found in that area, even though evidence suggests that several large forest fires have occurred.

Which statement best describes what happened?

Secondary succession occurred, followed by several primary successions.
Only secondary successions occurred.
Primary succession occurred, followed by several secondary successions.
Only primary successions occurred.

In a laboratory, nakisha mixes sodium hydroxide solution with an indicator called phenolphthalein. when combined, they create a pink solution. nakisha wonders if mixing other solutions with phenolphthalein will also create this pink color. how could she use the scientific inquiry process to explore it further?

Why do astronauts in the space shuttle weigh less?

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.