If the same antibiotic is used too many times it can become less effective against a certain bacteria this observation is the best explained by

What is the significance of the protein-lined pits? a. protein attracts other proteins needed for atp synthesis within the cell. b. protein-lined pits are able to transport one molecule at a time down the concentration gradient within the cell. c. the polarity of proteins allows other polar molecules to attach and be transported in the cell by transport channels. d. receptors within the pits allow ligands to fuse and be transported into the cell by endocytosis.

Which of the following was not a major animal on land during the carboniferous period? amphibians insects both a and b none of the above

Select the correct answer from each drop-down menu. the lac operon in e. coli regulates genes that code for enzymes required for breakdown of lactose. the lac operon is operon that is activated in the presence of .