My second question for today : Why do we ever have a blood moon?? What's the science behind it​

Geologists know that potassium-40 decays to argon-40, with a half-life of 1.3 billion years. if an analysis of a feldspar crystal in a sample of granite shows that 75 percent of the potassium-40 atoms have decayed to form argon-40, what is the age of the granite

Explain the value of statistics and other data to positive economics and to normative economics

Which of teh following would explain the importance of the trans-siberian railroad to russia's economy? (schoology test)