I think the correct answer from the choices listed above is the third option. The barrel of a gun is also known as bore. The barrel is the metal tube which the bullet is fired and the bore is the inside of the barrel. It is the one closest to the barrel so it must be the answer.
The correct answer is: the treated glioblastoma cells were cultured in the presence of an inhibitor from umbilical cord stem cells, but the control cells were cultured without the inhibitor.
It has been shown that treatment with injected umbilical cord stem cells has strong therapeutic effects on glioma models. Those cells produce anti-tumour substances, with inhibitory effects.
Control group does not include the treatment in order to observe the treatment.
Answer:
In C4 photosynthesis, where a four-carbon compound is produced, unique leaf anatomy allows carbon dioxide to concentrate in 'bundle sheath' cells around Rubisco. This structure delivers carbon dioxide straight to Rubisco, effectively removing its contact with oxygen and the need for photorespiration