The reasons why 241am smoke detectors are perfectly safe is because;
(i) The amount of americium is very little.
(ii) The aluminium core is where the detector is hosted.
(iii) The detector has a plastic cover.
(iv) Radiation is limited in penetrating power.
(v) There is a low number which is leaving the case.
(iv) ions get trapped by electrodes.
Answer:
A) the envelope of gases surrounding the Earth the envelope of gases surrounding the Earth
Explanation: A biosphere is layers of gas surrounding earth's atmosphere, the envelope of gases surrounding the Earth is the closest thing to that description.
