After two half-lives, the amount of radioactive substance remaining will be
A 25% of the initial parent nuclei.
B 75% of the initial parent nuclei.
C 50% of the initial parent nuclei.
D 25% of the daughter nuclei

A 25% of the initial parent nuclei.

Explanation:

One half life, you get 50%, two half lives you get 25% and you just keep dividing by 2 from there. :) Good luck my friend!

fdvwsa gfwsargebgeebbfwfwffw gwf   vgwgw gw f gwgw fgw v v dsv dwfff

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.