Which tissue produces lymphocytes and filters out impurities and harmful substances?

Which statements are true of a scientific theory but not a hypothesis

Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.

Which of the following is likely not involved in this example of ecological succession? a) the rotting remains of plants add to the fertility of the soil. b)the soil becomes so fertile that eel grass is replaced by other plant species. c) the roots from plants stabilize the sediment, keeping it in place. d) the concentration of salt becomes so high that all plant life is destroyed.