What factor slows transcription?
question 4 options:

rna polymerase

enhancer

repressor

activators

what enzyme transcribes mrna?
question 5 options:

rna polymerase

dna polymerase

galactase

lactase

Repressor slows down transcription.

RNA Polymerase enzyme transcribes mRNA from DNA.

Explanation:

Promoters are the 100 to 900 bps long sequence of DNA, that helps in the initiation of transcription. The transcription gets slow down as repressor bind to the promoter region hampering the attachment of RNA Polymerase enzyme which is responsible for transcription.

The process of transcription is the conversion of DNA into mRNA as told in the central dogma of molecular biology. Enzyme responsible for transcription is RNA polymerase. It is the first phase of gene expression, where DNA strand is copied into mRNA called a primary transcript.