Testable, possible explanation for a scientific problem
The right answer is All answer options describe plasmids.
A plasmid is a natural or artificially modified circular DNA molecule for use in biological research.
The researchers use the plasmids to insert a DNA fragment of interest, thanks to the cloning cassettes. They can clone genes to express proteins or RNAs and analyze them.
I think you just answered your question. They encourage adolescents to eat calcium-rich foods because it aids in bone formation, like you said.
