It's either c or d. But I'd go with D.
Preset trays hold all instruments need in a particular procedure. It is put together in a tub and trays are easily exchanged for other instruments. It is designed to increase efficiency in operations, minimize waiting time and space is reconfigured.
In a sample of double-stranded DNA, if the nitrogenous base guanine is 19%, then the nitrogenous base adenine will be 31%
Explanation:
In a double-stranded DNA, the four nitrogenous bases bind and pair together. The purine bases guanine (G) and adenine (A) pair with pyramidine bases cytosine (C) and thymine (T) respectively. The pairing will be between G-C and A-T bases.
According to Chargaff’s Rule, the percentage of each nitrogenous base will be equal in a pair. So the percentage of G will be equal to percentage of C and the percentage of A will be equal to percentage of T.
So if the guanine percentage is 19%, then applying Chargaff’s rule, cytosine will also be 19%
The remaining 68% will be shared with the adenine and thymine pair, of which adenine will be of 31% according to Chargaff’s rule.
