Which of the following is a general theory in geography that can be used to quantify and predict the interaction between two cities based on population sizes, distance between the places, the number of migrants moving from one place to the other, or the flow of trade goods between the two locations?.

How many miles is each lap?

The answer would be  b. hope this !

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.