Answer:When a cell needs to move a molecule many times, it uses vesicles. Vesicles are cellular organelles that are composed of a lipid bilayer. You can think of vesicles as cellular envelopes that are used to transport materials from one place to another. Vesicles also function in metabolism and enzyme storage as well.
Explanation:
Depends on the situation Usually the hardest would be blood samples of the Unsub. Again It depends on the situation.
The answer is protect the body from infection by pathogens
The physical barrier is made of epithelial cells, mostly will be keratinized to increase their sturdiness further. They will impede the pathogen physically by barricading the cells, makes the pathogen could not invade deeper part of the body. Histamine and antibodies should be the role of immune cells, not epithelial.
Transfer water hope this helps!