Answer:
Left amount of Polonium-210 after 115 days will be 4.5927 microgram
Explanation:
We have given initial mass of Polonium-210 
Decay rate x= 0.502% = 0.00502
Time t = 115 days
We have to find the left amount of Polonium -210 after 115 days
We know that left amount is given by

So left amount of Polonium-210 after 115 days will be 4.5927 microgram
Exactly what the person above said!
Answer:
bc oxygen contributes to muscle performance on and off the field.
A radioactive element is an element which is subject to spontaneous degeneration of its nucleus followed by the emission of alpha, beta and gamma particles. All elements with atomic numbers greater than 83 are radioactive.
The given phrases that describe radioactive elements are-
They have a consistent number of particles
- the particles are alpha, beta and gamma particles.
They have a half-life that determines their rate of decay.
Explanation for other options:
Not all elements occur in nature. Radioactive decay rates may not be constant as the decay happens when a radioactive substance emits a particle. It is not possible to predict exactly when a given atom of a substance will emit a particular particle. When the radioactive element release energy and particles, it decays.