The question is incomplete. Th ecomplete question is as following:
All of the following protect the skin and mucous membranes from infection EXCEPT
A) multiple layers of cells.
B) tears.
C) saliva.
D) HCl.
E) the "ciliary escalator."
Answer: D) HCl.
Explanation:
- The epidermis, the outer layer of the skin provides waterproofing and serves as a barrier to infection and other laers also sustain any type of injury.
- Tears wash out foreign bodies which enter the eye. In addition, tears contain a substance called lysozyme which has an antibacterial function and works to prevent microbial invasion and infection.
- Saliva protects against infection, especially via the innate immune system. This mechanism is an important first-line protection against bacterial and viral infection
- The mucociliar escalator is within the conducting airways and is composed of mucus and cilia that transfer the mucus up and out of the lungs where it can be removed by coughing or swallowing,
Whereas HCL helps in the digestion process.
Hence, the correct option is D.
Answer:
The correct answer would be B. Controlling coordination in the body.
Central nervous system is one of the parts of nervous system that includes brain and spinal cord.
The brain is located in the skull and serves as the controlling and processing center of the body. For example, visual processing takes place in occipital lobe of the brain, planning, reasoning, speech, movement, emotion et cetera are processed in frontal lobe of the brain.
The spinal cord is attached to the brain through brain stem. It connects the central nervous system with peripheral nervous system. It also in regulation of reflex actions.
Answer:
Prokaryotes play several roles in the nitrogen cycle. Nitrogen-fixing bacteria in the soil and within the root nodules of some plants convert nitrogen gas in the atmosphere to ammonia. Nitrifying bacteria convert ammonia to nitrites or nitrates. ... Denitrifying bacteria converts nitrates back to nitrogen gas
Explanation:
