The sphincter is a of muscle at an opening.
a. strip
b. pack
c. ring
d. band
e. network

The trp operon in e. coli regulates genes that code for enzymes required for synthesis of the repressible operon. when tryptophan is not available amino acid tryptophan. the trp operon is a in the environment, the trp repressor protein activeinactiveregulated. therefore, rna polymerase can bind to the genes to begin transcription.

Which of these organisms have the greatest amount of cell specialized

Four types of motile cells in human body?