I think the answer is B lil bruh
Answer: Option B
Explanation: The first line of defense acts a barrier and does not allows the foreign materials to enter inside the body. It includes chemical and physical barriers that are always ready to protect the body from infection.
Example: Skin and mucous membrane.
Skin is largest organ and it acts as a barrier between pathogens and human body. It acts a waterproof material and the pathogens cannot get inside through skin unless the skin is broken.
Mucous membranes also acts as first line of defense and breaks the cell wall of many bacteria entering through the openings of the body.
So, skin and mucous membrane are the first line of defense.
I think TRUE
Humans alteration of the global environment has triggered the sixth major extinction event in the history of life and caused widespread changes in the global distribution of organisms.
<span>Symbols for lipids is C and H.
It also contains Nitrogen and phosphorous. DNA or RNA their symbol is C, H, O, N, P. Protein contains both sulfur and selenium which are C, H, O, N, P. Proteins are subunits of amino-acids.
Proteins can be carriers, signaling structural and also immune responses. They are made of the nucleus.
Lipids are hydrophobic and are naturally found in the body to mean that they don't mix with water reason being they are non-polar. Lipids make up phospholipids bilayer.
DNA is supercoiled, and their backbone which is made up of phosphate and sugars groups.</span>
