why would a radioactive element need to have a known rate of decay in order for it to be useful as a dating tool?

Suggest two reasons why irrigation is important for human development of the desert (4 marks)

Ascientist is explaining how background cosmic radiation gives evidence of the big bang theory. she says that radiation has been detected everywhere equally as heat in the universe and is increasing. this has been shown to be residual radiation from the big bang. what error did the scientist make?

All of the following are reasons why deserts extremely susceptible to wind erosion except a. they lack major root systems b. they contain thin, dry soil c. they have very few plants and trees d. they are extremely hot and lack water