How do exons and introns differ?

exons code for proteins.

introns code for proteins.

exons do not have a code.

introns do not have a code.

The term facultative anaerobe refers to an organism that

Pls me i need this ! each cell has genes activated depending on it's job and what kind of cell it is. it is the presence of that causes the repressor protein to fall off and unblock the gene on the lac operon. if a gene is turned on then it is being an additional circular chromosome found in some bacteria that is used in genetic engineering.

What is the purpose of transcription? a. to copy the nucleotide in dna b. to form rna molecules from dna c. to produce a nucleic acid sequence from an amino acid sequence d. to link amino acids together to form stands of protein