Why can water have no net charge but have slight charges in different parts of the molecule? A. The oxygen end is slightly negative and the hydrogen end is slightly positive.
B. The hydrogen end is slightly negative and the oxygen end is slightly positive.
C. The hydrogen and oxygen ends change in polarity.
D. Because it is hydrophobic.

A

Explanation:

The unequal sharing of electrons gives the water molecule a slight negative charge near its oxygen atom and a slight positive charge near its hydrogen atoms.

Lysozyme - Chemical barrier;
Lysozyme is a substance found in saliva, tears, and mucus that destroys the cell wall of bacteria
Skin- physical barrier
The skin has closely packed cells and it is  tough, flexible and also water proof. 
Phagocytes -Biological barriers;
They are types of white blood cells that help protect against pathogens. 
Langerhans cells- Biological barriers;
These are specialized cells in the skin that identify pathogens that enter the body and carry them to the lymph nodes for destruction. 
Acid and Oil (skin secretions) - Chemical barriers;
These are secretions from the skin that help to keep microorganism from entering the body
Sneezing and coughing - Physical barriers.
Type of reflexes that helps keep microbes and pathogens from gaining access to the body systems.