The first line of defense involves which structure(s)?
a- t-cells,
b- skin,
c- blood,
d- b-cells

Your answer is B- skin.

Your answer is B- skin.

The correct answer is option B, that is, skin.

Explanation:

The innate immune system is considered as the first line of defense. This immune system is formed of defenses against the infections, which can be stimulated instantaneously after the attack of a pathogen. The innate immune system is basically formed of barriers, which works to keep bacteria, viruses, parasites, and other foreign agents away from the body or restrict their tendency to disperse and move all over the body.  

The innate immune system comprises physical barriers like the gastrointestinal tract, skin, the nasopharynx, the respiratory tract, and body hair. It also comprises defense mechanisms like mucous, secretions, tears, saliva, sweat, and gastric acid. Apart from this innate immune system also comprises certain general immune responses like complement, inflammation, and non-specific cellular responses.  

The correct answer is option B, that is, skin.

Explanation:

The innate immune system is considered as the first line of defense. This immune system is formed of defenses against the infections, which can be stimulated instantaneously after the attack of a pathogen. The innate immune system is basically formed of barriers, which works to keep bacteria, viruses, parasites, and other foreign agents away from the body or restrict their tendency to disperse and move all over the body.  

The innate immune system comprises physical barriers like the gastrointestinal tract, skin, the nasopharynx, the respiratory tract, and body hair. It also comprises defense mechanisms like mucous, secretions, tears, saliva, sweat, and gastric acid. Apart from this innate immune system also comprises certain general immune responses like complement, inflammation, and non-specific cellular responses.  

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

your answer would be “dry”