<span>Coding sequences that regulate gene expression </span>
Animal cells have DNA in the nuclei while plants have their DNA in the nuclei and chloroplasts
After the macrophage fails the Helper T Cell stimulates the B cells (create antibodies) if pathogen is extracellular and Cytotoxic T Cells (killer T cells, release perforin) if pathogen is intracellular. Once the pathogen is killed the B Cells create Memory B Cells and the Killer T Cells create memory T Cells.
Hopefully I helped answer your question :)
Receptor receives chemical signals came from the cell's outside environment. It is made up of protein molecule. The correct answer for the question above is letter a. Receptor protein allows one or <span>a few specific molecules to pass across the membrane.</span>
It’s under chemical change.
