What is half-life?
a.) the time it takes for a radioactive atom to lose half its electrons
b.) the time it takes for half of any number of radioactive atoms to decay
c.) the average time it takes for any element to disappear completely
d.) the time it takes for a radioactive atom to lose half its nutrients

it's b

Explanation:

I just took a test with this question and it's b

i think it's c. i'm not sure but i think so.

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.