1.
How often should you check your oil?

I generally recommend checking your car's oil at least once a month, if not more frequently. Your oil probably only needs to be changed between two and four times per year, which means that if you only rely on oil changes, you could have an unchecked issue for months before it's fixed.

explanation:

japan participated in world war i from 1914 to 1918 in an alliance with entente powers and played an important role in securing the sea lanes in the west pacific and indian oceans against the imperial german navy as the member of the allies.

d. china

good luck

d is the best choice