Which of the following is most likely to mark the boundary between two continents?
a. river.
b. group of hills.
c. a lake.
d. an ocean.

Of the options provided, that which most likely marks the boundary between two continents is

Oceans are large bodies of water that take up to 70% of the earth's surface. Continents are made up of countries. Due to their size, oceans will most likely be boundaries for continents.

97% of the water in the earth comes from oceans. The Arctic ocean separates the European and Asian continents.

The North Pacific Ocean separates North America from Asia, and the Atlantic Ocean separates Europe from North America.

Summarily, an ocean is most likely to mark the boundary between two continents.

Learn more about oceans here:

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battle of saint-mihiel, (12–16 september 1918), allied victory and the first u.s.-led offensive in world war i. the allied attack against the saint-mihiel salient provided the americans with an opportunity to use their forces on the western front en masse.

explanation:

equal pay act of 1963. the equal pay act, signed in to law by president john f. kennedy on june 10, 1963, was one of the first federal anti-discrimination laws that addressed wage differences based on gender. they felt that this would prevent employers from undercutting future wages for men.