`.^90 Sr` from the radioactive fall out from nuclear bomb ends up in the bones of human being through the milk consumed by them. It causes impairment of the production of res blood cells.
The energetics `beta-`particles emitted in the decay of `.^90 Sr` damage the bone marrow.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are truw but reason is not correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer

A

Explanation

Assertion is true `""_(38)^(90)Sr` decays to `""_(39)^(90)Y` by the emission of`beta-rays`.Sr gets absorbed in bones along with calcium.
Reason is also true. `""^90Seoverset(beta)to""^(90)Y`
Strontium decays to Yitrium.This emits `beta-rays`of very high energy.Sr does not emit`gamma-rays`.The damage is by the`beta-rays`Only.