Residents of moldova are mainly a. russian b. ukrainian c. serbian d. romanian

The correct answer is - d. Romanian.

Moldova is a country where there's multiple ethnic groups that make up solid percentages in the total population, including Romanians, Russians, Ukrainians, Gagauz, Bulgarians, making it a multicultural and multi-ethnic country.

It has to betaken in consideration that even though most of the people in Moldova have Romanian origin and ethnic background, and it is thought that around 85% of the population is Romanian, still the majority of the people, in the last census, declared themselves as having a Moldovan ethnicity. Considering this, since the people feel like that, and everyone has the right to declare their nationality by their will and feelings, the people with Moldovan ethnicity will be dominant, while the Romanians will come second.

answer ( groundwater);

heat from the core of the earth causes convection currents to occur in the mantle. these currents slowly move the crust around.