The answer is; D
The porous rock is able to absorb water from precipitation. The water resides in the pores of the rock. The impermeable rock later, which does not allow water to pass through it, allows more water to hold in the porous rock and making the local water table to rise. The water in the porous rock, therefore, can be accessed through wells or a water spring can develop.
Any substance that triggers an immune response is an antigen(s).
I think tissue or a nucleus
Answer:
Producing toxic substances to suppress host response
Ecosystems disturbed by a nature will be eventually restored unless it's a really big cataclysm, but most of the ecosystems are now a human caused disturbance. For example there are plenty of species which are already extinct or nearly extinct because of hunting industry.
