In prokaryotes, the DNA dependent RNA polymerase is a holoenzyme that is made of polypeptides (α₂ββ′ω)σ. It is responsible for initiation, elongation and termination during transcription. 

DNase degrades DNA. 

DNA dependent DNA polymerase is involved in replication of DNA. 

DNA ligase joins the discontinuously sysnthesised fragments of DNA.

Hence, the correct option is (C).

During trisubstitution, the acetanilide group attached to the benzene ring is more electron donating than the methyl group attached, owing to +M effect, and therefore, the incoming electrophile would prefer ortho w.r.t the acetanilide group.

Hence, the correct option is (A).

When two solutions of equal volumes are mixed, precipitation will occur. The precipitation only occurs when the product is no longer soluble in the solvent. This threshold is given by the K_sp value.

Parsec, unit for expressing distances to stars and galaxies, used by professional astronomers. It represents the distance at which the radius of Earth's orbit subtends an angle of one second of arc.

Hence, the correct option is (A).

Animal cells after removal of nuclei still contained DNA. The source of this DNA is 'Mitochondria'.

Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA. This genetic material is known as mitochondrial DNA or mtDNA. Thus, after the removal of nuclei, the cell still has mtDNA.

Hence, the correct option is (B).

Insulin is a hormone that reduces blood glucose and was commercially first produced by the pharmaceutical company Eli Lily.

The Indian Government has set up organizations such as GEAC (Genetic Engineering Approval Committee), which will make decisions regarding the validity of GM research and the safety of introducing GM-organisms for public services.

PCR stands for Polymerase Chain Reaction. In this reaction, multiple copies of the gene (or DNA) of interest is synthesized In-vitro using two sets of primers (small chemically synthesized oligonucleotides that are complementary to the regions of DNA) and the enzyme DNA polymerase.

The construction of the first recombinant DNA emerged from the possibility of linking a gene encoding antibiotic resistance with a native plasmid (autonomously replicating circular extrachromosomal DNA) of Salmonella typhimurium. Stanley Cohen and Herbert Boyer accomplished this in 1972 by isolating the antibiotic resistance gene by cutting out a piece of DNA from a plasmid that was responsible for conferring antibiotic resistance.

Hence, the correct option is (B).