Radon and Thoron are the most significant sources of radiation exposure to people living in the United States accounting for 37% of total radiation exposure.
These are nuclides that are produced from the radioactive decay of materials especially in consumer products and through natural processes such as the decay of radium.
The correct answer is A. This is because undeveloped meaning they don't have access to any of the other offered answers
Answer:
a system, or a group of interconnected elements, formed by the interaction of a community of organisms with their environment.
Explanation:
They must be able to reproduce fertile offspring.
