I believe the answer is A
Since the half-life is 4.5 billion years, two half-lives would have elapsed after 9 billion years.
<span>If you start with 400 g, half decays during the first half-life, leaving 200 g. </span>
<span>During the second half-life, half of the 200 g decays, leaving 100 g.</span>
Explanation:
Plasma is the clear, straw-colored liquid portion of blood that remains after red blood cells, white blood cells, platelets and other cellular components are removed. It is the single largest component of human blood, comprising about 55 percent, and contains water, salts, enzymes, antibodies and other proteins.
