The half-life of a radioactive element is the time it takes for:
A) half of the radioactive atoms to double themselves.
B) half of the radioactive atoms to decay into isotopes.
C) the radioactive atoms to increase by half of its initial quantity.
D) the radioactive atoms to increase to 1.5 times of its initial quantity.
Question 2
Which of the following is true of meteors?
A) They are not stars.
B) They orbit Terrestrial planets.
C) They are composed of frozen water.
D) They do not contain rock or metal.
