What percent of the earth's surface does the ocean cover? a) 21%
b) 50%
c) 75%
d) 78%

The ocean covers more than 70 percent of the surface of our planet. It's hard to imagine, but about 97 percent of the Earth's water can be found in our ocean. Of the tiny percentage that's not in the ocean, about two percent is frozen up in glaciers and ice caps.

Explanation: it is 75%

d. stage 4

explanation:

the existence of some kind of demographic transition is widely accepted in the social sciences because of the well-established historical correlation linking dropping fertility to social and economic development.[1] scholars debate whether industrialization and higher incomes lead to lower population, or whether lower populations lead to industrialization and higher incomes. scholars also debate to what extent various proposed and sometimes inter-related factors such as higher per capita income,lower mortality, old-age security, and rise of demand for human capital are involved.[2]