During the middle ages, the city of Constantinople was A
the largest city in the world

B
protected by high mountains and deserts

C
the holiest city to Christians

D
the home of the Pope

Water flows along the east coast and across the western tropical pacific towards south america, while they both are directed towards that way,  el niño does not directly affect the southern flow of water along the coast. 

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.

Explosive eruptions are the most hazardous, involving large volumes of tephra and gases emitted from the volcano. lahars, pyroclastic flows, ashfall, and many other volcanic hazards are commonly associated with explosive eruptions. explosive eruptions are very dangerous. basically, any form of hazard can occur.