Which isotope has a relatively short half-life

At which boundary does subduction stop occurring, resulting in a mountain range?

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

Who developed the theory of plate tectonics?