The answer would be the last option
Answer:
<u>Radon </u>in door source of air pollution.
Explanation:
- From all Pollutant and sources found in the interior of the homes like the pet dander and molds, pesticides and asbestos. Radon a chemical element found in homes having an atomic number of 86. It is a radioactive and odorless tasteless natural gas.
- Through the radon is non-reactive elements, it can be oxidized with compounds of fluoride. It has no stable isotopes characterized bt unstable mass. In the mining industry, it caused due to the exposure from the released air.
- Radium-226 is used to produce the radon which is found in uranium ores and phosphate rocks. An estimate of about 2.4 billion curies of radon is released every year into the soil. This pollutant can also be found in water bodies and even in construction sites.
The failure was due to reduced support from the Soviet Union when North Korea aligned more with China and military pressure from the US
