Potassium-40 has a half life of 1.251×billion<span> years</span><span>. To determine the percentage potassium-40 remaining after 3.9 billion years, divide
3.9 by 1.251, = 3.12.
This is the number of times the original amount of potassium-40 reduces by 50%. The remaining percentage is therefore 100%/(3.12 * 2) = 16.03%.</span>
Answer:
Gas exchange during respiration occurs primarily through diffusion. Gas molecules move from a region of high concentration to a region of low concentration. Blood that is low in oxygen concentration and high in carbon dioxide concentration undergoes gas exchange with air in the lungs.
Explanation:
With every other lever 10% of the energy with be transferred. In this case:
Primary Producers (500)
1) First- level consumer. (50)
2) Second-level consumer. (5)
3) Third- level consumer. (0.5)
Remember the formula is:
(Primary Producer) __units X 10%= __
In this case: 500 units X 10%= 50
