Final answer:
Radiophosphorus is the element used to study fertilizer absorption and is also used in cancer treatment.
Step-by-step explanation:
The element used to study fertilizer absorption and is also used in cancer treatment is
Radiophosphorus. Radiophosphorus refers to the radioactive isotope of phosphorus, specifically ^32P. In the study of fertilizer absorption, radiophosphorus can be used to track the movement and uptake of phosphorus in plants. Additionally, radiophosphorus is also used in cancer treatments, particularly in radiation therapy to target and destroy cancer cells.
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