A 7.50 g sample of potassium 40 was collected after 8.757 x 10^9 years 0.05859 g of the sample remained. what is the half life of potassium 40?

Pastoral farming is best described as a. a method of raising livestock and moving herds b. an african method of agriculture c. a method of cultivating crops on poor soils d. a common method of desert farming select the best answer from the choices provided a b c d