The changes in the land in the path of a receding glacier is a good example of .

Magma is outside the volcano  and lava is inside the volcano. 

D. a mountain abd are made by volcanos and tectonic plates

When a lake, river or other aquatic  system  becomes  eutrophic, it can have serious negative effects on other organisms like fish, birds and even people.if an algal bloom is so bad that it causes wide-spread death  in  the  water, the organisms that die will all sink to the bottom and start to decompose.