You have an isotope with a half-life of 200 years How much of the original material is left after 600 years?

Look at the photo i can’t do geography

Based on what you know about the location of the earth in relation to the sun, why is this called the goldilocks zone in other galaxies? a. it's a region that exhibits a weak gravitational pull, thus maintaining a safe distance from the sun. b. it's an area that doesn't experience any major weather events that could cause mass extinctions. c. it's an area that's an optimal distance from the sun for potentially supporting life. d. it's a region that's unaffected by asteroid or meteor impacts.

Which phrase describes the time it takes for a planet to make a complete rotation