Gel electrophoresis is a technique used to separate DNA fragments according to their size. This is from Khan academy so I believe it is reliable.
Answer:
There was no sulfur compound added to the medium, that could be used as an electron donor.
Explanation:
Bacteria that use light for energy requirements mean that they get their energy from photosynthesis and transferring energy through the molecules.
Bacteria play a major part in the reductive and oxidative cycle of the sulfur which is mediated by the help of photosynthetic bacteria, so the sulfur or sulfur compounds are major requirements for their growth in the habitat or the medium.
Thus, the correct answer would be- There was no sulfur compound added to the medium, that could be used as an electron donor.
The epithelial cell will have 38 chromosomes
A 2n or 2(19) = 38 chromosomes. This is because n is called haploid number of chromosomes; the number of chromosomes present in the gametes. Epithelial cells like other body cells divides through the process of mitosis; therefore; the parent cells yields daughter cells with the same number of chromosomes (diploid). The other haploid (n) number is present in the gametes which divides by the process of meiosis.
B. cellular respiration, Hope this helps!