A period is the time required for half of the atoms of a radioactive element to decay

Radioactive Decay – Measuring the Age of the Solar System The half-life of a radioactive element is the amount of time it takes for half of the atoms in a sample to decay from an unstable state to a stable one.

Explanation:

ecological efficiency: % of usable energy transferred as

biomass from one trophic level to the next typical is 10% efficient (90% of

energy is lost),is diagramed as the pyramid of energy flow. then osprey eagle

are tertiary consumer and the shrimp are primary consumer, so to balance

mass of shrimp (1/0.1) / 0.1 = 100 kg