The first letter 'H' indicates the genus of the organism, from which the enzyme was isolaled, i.e. H-genus, Haemophilus.
The roman number (IIl) denotes the sequence in which the restriction endonuclease from that particular genus, species and strain of bacteria have been isolated, i.e. third restriction endonuclease to be isolated from this species.

Tumour inducing (Ti) plasmid of Agrobacterium tumefaciens is modified into a cloning vector by removing/ altering the gene responsible for its pathogenic property.

The recombinant DNA can multiply as many times as the copy number of the plasmid vector. thereby determning the yield of recombinant protein So, higher the copy number of the plasmid vector, higher will be the yield of recombinant protein.

Type II restriction enzyme obtained from Escherichia coli, called EcoRI.

If the restriction enzymes have more than one recognition site in a vector, than the vector itself will get fragmented on treatement with the restriction enzyme.

CaCl₂ increases the efficiency of the competent cells to pick up DNA  through the pores in its cell wall

Hepatitis-B vaccine.

Proteases remove the proteins associated with the DNA.

Competent refers to the ability of the host cell to take up tha alien or recombinant DNA

No, because exonucleases will remove the nucleotides from the ends DNA molecule and not at any particular desired region.