instruction:
Given a scientific question, generate a correct answer to it.
question:
What term refers to the sequence of community and ecosystem changes after a disturbance?
answer:
ecological succession

question:
What is the name for the stratospheric gas layer that protects living things from uv radiation?
answer:
ozone layer

question:
Spiders use the hydrostatic pressure generated by an open type of what anatomical system to extend their legs?
answer:
circulatory