Half-life is
a. constantly changing.
b. half of the lifetime of an unstable nucleus.
c. the time required for one-half of an unstable nuclei to decay.

What happens when light is scattered?

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)