Although Moldova has hilly landscape, it has throughout its history. been independent

remained a world power

been conquered

remained isolated

Ba rock that formed 1,400 million years ago!

Don't depend on this but logically i think c

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.