The half-life of l-131 is 8 days. What mass of a 4 gram sample of l-131 remains after 32 days?

Explain how light energy is turned into chemical energy? ! due tomorrow!

On his trip to the galapagos islands, darwin determined that animals on the islands

The table below shows the elements that mainly comprise each of the four layers of earth: elements in layers layer main elements crust oxygen, silicon mantle iron, magnesium outer core iron, nickel inner core iron which of these elements make up the layer that is 0.2 to 1.1 percent of earth's total diameter?