Fairly sure that would be secondary succession.
Controls what goes in and out of a cell
The purpose of ethical guidelines for handling of experimental subjects is to ensure the safety and well-being of all living creatures in an experiment.
Ethical guidelines include issues such as human rights, animal welfare, safety compliance with the law, conflicts of interest, health standards..
Ethical guidelines are the norms for the acceptable and unacceptable behaviors of the researchers.
I think the answer is Specialized cells!
