Suppose that there's a river which begins in Canada and flows through the United States before finally reaching the ocean. Which of the following activities by Canada would most likely cause problems for the United States? A.
requiring safety inspections for river boats
B.
imposing stricter water pollution laws
C.
starting fish farms near the river
D.
constructing a dam to generate electricity

B. imposing stricter water pollution law

D: constructing a dam

Explanation:

A dam would likely reduce the flow of water from the Canadian side to the US side.

the 4th option is the answer

giant impact theory - the moon was formed from the collision between earth and another mars-sized body.

colliding planetesimals hypothesis - the moon was formed from the same cloud of material as earth.

capture hypothesis - the moon was locked into orbit by earths gravity as it was passing by it.

accretion hypothesis - the moon was formed from collisions and combining of planetesimals.

i think this is right, if not and you know better let me know.