HELP ASAP PLZ EARTH SPACE SCIENCE
1. An element has a half-life of 30 years. If 1.0 mg of this element decays over a period of 90 years, how many mg of this element would remain?

2. A 2.5 gram sample of a radioactive element was formed in a 1960 explosion of an atomic bomb at Johnson Island in the Pacific Test Site. The half-life of the radioactive element is 28 years. How much of this element will remain after 112 years?

3. An element has a half-life of 29 hours. If 100 mg of the element decays over a period of 58 hours, how many mg of the element will remain?

Need help asap plz !!

Spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

What would happen if the krill were removed from the food web

Benito is doing research on the effects of florida's elevation on its climate. his notes include the following: 1. the average elevation of florida is 30 m above sea level. 2. the highest point in florida is britton hill, which is 105 m above sea level. 3. the change in temperature from 0 m to 1,000 m is 7 °c. what can benito conclude about the effects of florida's elevation on its climate? a.) florida typically experiences cold temperatures and temperature changes within a narrow range. b.) florida typically experiences cold temperatures and temperature changes within a broad range. c.) florida typically experiences warm temperatures and temperature changes within a narrow range. d.) florida typically experiences warm temperatures and temperature changes within a broad range.