Can someone plz explain the calculations for this?

The formation of the planet uranus is estimated to have occurred approximately when?

Which ecosystem best fits the characteristics listed below? which ecosystem best fits the characteristics listed below? ii. seasonal migrations of millions of wildebeests, zebras, and elephants iii. large numbers of predators, such as lions iv. acacia trees and grasses a. the congo rainforest b. the african mangroves c. the serengeti grasslands d. the sahel

Pollution from one country can affect another. for example, south korea is especially affected by pollution and dust storms that come from