A 128 gram Radium-226 sample with a half-life of 2.25 billion years is found. How many grams will remain after two half-lives?

What changes occur in the brain during the teenage years? 25 points, someone me out!a.) thinking becomes slower as the brain grows larger. b.) connections between neurons become stronger and faster. c.) unused neurons fuse together to form larger, better functioning neurons. d.) more neurons are developed.